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josmiceli answered: 9815 problems
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Rational-functions/408202: Find the vertex, line of symmentry, and the max/min value of f(x)=1/5(x+2)^2+2, is the valuef(=2)=2 min or max and graph. I am having problems trying to solve this.
1 solutions

Answer 287641 by josmiceli(9817) About Me  on 2011-02-12 17:41:07 (Show Source):
You can put this solution on YOUR website!
f%28x%29+=+%281%2F5%29%2A%28x+%2B+2%29%5E2+%2B+2
I can say z+=+x+%2B+2, then
f%28z%29+=+%281%2F5%29%2Az%5E2+%2B+2
In an equation of the form
f%28z%29+=+a%2Az%5E2+%2B+b%2Az+%2B+c, the z-coordinate of
the vertex is at -b%2F%282a%29, but b+=+0
here, so (0,f(0)) is the vertex, and to find y
f%280%29+=+%281%2F5%29%2A0%5E2+%2B+2
The vertex is at (0,2)
Now I translate this to (x,f(x))
z+=+x+%2B+2
0+=+x+%2B+2
x+=+-2
f%28-2%29+=+%281%2F5%29%2A%280%29%5E2+%2B+2
f%28-2%29+=+2
(x,f(x)) = (-2,2)
The line of symmetry is x+=+-2
The graph is a min at f%28x%29+=+2
Here is the plot:
+graph%28+400%2C+400%2C+-10%2C+10%2C+-10%2C+10%2C+%281%2F5%29%2A%28x+%2B+2%29%5E2+%2B+2%29+


Trigonometry-basics/408205: How do I figure out the exact value of 11pi/2? I need to know this and other questions like this for my homework and cannot figure it out since I don't see it on the unit circle. Another is tan(6pi). Can you please explain to me how to get the correct answer to these kinds of questions, the more detail the better! Thanks!
1 solutions

Answer 287637 by josmiceli(9817) About Me  on 2011-02-12 17:13:14 (Show Source):
You can put this solution on YOUR website!
Think of this as 11%2A%28pi%2F2%29
The question to ask is: How many pi%2F2 radians will
get you from pi%2F2 back to pi%2F2 again?
The answer is 4 and any multiple of 4,
so 4, 8, 12, 16, etc.
Now I can restate the problem as:
11%2A%28pi%2F2%29+=+8%2A%28pi%2F2%29+%2B+%283%2Api%29%2F2%29
The 1st part just brings me back to where I started, and I'm
left with 11%2A%28pi%2F2%29+=+%283%2Api%29%2F2
------------------------------------
I'll show you a tougher example:
511%2A%28pi%2F4%29
Starting from pi%2F4, how many multiples of pi%2F4 will
bring me back to pi%2F4? The answer is8,
and any multiple of 8, like 8,16,24, etc.
511%2F8+=+63+%2B+7%2F8
Ignore the 63 because that is how many times you go
completely around and back to pi%2F4, so the answer is:
511%2A%28pi%2F4%29+=+%287%2Api%29%2F8


Rational-functions/408152: Classify each system of equation as independent, dependent, or inconsistent. Solve independent systems by graphing.
1+y=x
x+y=1
1 solutions

Answer 287603 by josmiceli(9817) About Me  on 2011-02-12 13:44:25 (Show Source):
You can put this solution on YOUR website!
Get in the form y+=+mx+%2B+b
1+%2B+y+=+x
subtract 1 from both sides
(1) y+=+x+-+1
and
x+%2B+y+=+1
subtract x from both sides
(2) y+=+-x+%2B+1
These have different slopes, so they must be independent
Here's the plot:
+graph%28+400%2C+400%2C+-10%2C+10%2C+-10%2C+10%2C+x+-+1%2C+-x+%2B+1%29+


Graphs/408148: How to Graph the inequality on a plane
5y-6x>30
1 solutions

Answer 287601 by josmiceli(9817) About Me  on 2011-02-12 13:38:31 (Show Source):
You can put this solution on YOUR website!
First get it into the form y+%3E+f%28x%29 or y+%3C+f%28x%29
5y+-+6x+%3E30
Add 6x to both sides
5y+%3E+6x+%2B+30
Divide both sides by 5
y+%3E+%286%2F5%29%2Ax+%2B+6
Now, I'll plot this
+graph%28+400%2C+400%2C+-10%2C+10%2C+-10%2C+10%2C+%286%2F5%29%2Ax+%2B+6%29+
The graph is all the points that are above this line, but
not including the line itself.
A good way to check is to pick a point that is below the
line and make sure that it does not satisfy the inequality.
Like (5,11)
11+%3E+%286%2F5%29%2A5+%2B+6
11+%3E+6+%2B+6
11+%3E12 not true
so, (5,11) is not part of the graph of the inequality


Numbers_Word_Problems/408137: Andrew has $446 in ten dollar, five dollar, and one dollar bills. There were 94 bills in all, and 10 more five dollar bills than ten dollar bills. How many one dollar bills did Andrew have?
1 solutions

Answer 287598 by josmiceli(9817) About Me  on 2011-02-12 13:26:05 (Show Source):
You can put this solution on YOUR website!
t = number of $10 bills
f = number of $5 bills
n = number of $1 bills
given:
(1) 10t+%2B+5f+%2B+1n+=+446
(2) t+%2B+f+%2B+n+=+94
(3) f+=+t+%2B+10
There are 3 equations and 3 unknowns,
so it's solvable
Subtract (2) from (1)
(1) 10t+%2B+5f+%2B+1n+=+446
(2) -t+-+f+-+n+=+-94
9t+%2B+4f+=+352
Substitute (3) into the result
9t+%2B+4%2A%28t+%2B+10%29+=+352
9t+%2B+4t+%2B+40+=+352
13t+=+312
t+=+24
and, since
f+=+t+%2B+10
f+=+34
and
(2) t+%2B+f+%2B+n+=+94
24+%2B+34+%2B+n+=+94
n=+94+-+58
n+=+36
Andrew had 36 $1 bills
check answer:
(1) 10t+%2B+5f+%2B+1n+=+446
(1) 10%2A24+%2B+5%2A34+%2B+1%2A36+=+446
240+%2B+170+%2B+36+=+446
446+=+446
OK


Expressions-with-variables/408144: Finding Degrees:
Is it true that when finding the degree of a polynomial that you look for the highest exponent?
1 solutions

Answer 287594 by josmiceli(9817) About Me  on 2011-02-12 13:13:05 (Show Source):


Geometry_Word_Problems/408145: A 105-inch is cut into two pieces. One piece is two times the length of the other. Find the lengths of the two pieces.
1 solutions

Answer 287592 by josmiceli(9817) About Me  on 2011-02-12 13:12:32 (Show Source):
You can put this solution on YOUR website!
Let one of the lengths = x
The other length = 105+-+x
given:
x+=+2%2A%28105+-+x%29
x+=+210+-+2x
3x+=+210
x+=+70
and
105+-+x+=+35
The lengths are 70 and 35


Travel_Word_Problems/408142: A family is going on a trip. If they travel at 65 mph for one hour, and then their speed increases to 75mphfor 45 minutes, and then the speed decreases to 65mph for the next 45 minutes how many
miles would they have driven?
1 solutions

Answer 287590 by josmiceli(9817) About Me  on 2011-02-12 13:08:58 (Show Source):
You can put this solution on YOUR website!
65%2A1 (miles/hour)x(hour) + 75%2A%283%2F4%29 (miles/hour)x(hours) + 65%2A%283%2F4%29 miles/hour)x(hours)
65+%2B+%283%2F4%29%2A%2875+%2B+65%29
65+%2B+%283%2F4%29%2A140
65+%2B+105
170
They drove 170 miles


Trigonometry-basics/408127: How can one divide fractions? For the cot pi/3 = 60 degrees, it's x divided by y, which would be 1/2 divided by square root of 3/2. I don't understand how the answer comes out to be square root of 3 over 3...? Is it something I just have to memorize or can it be worked out? Sorry if this is a really obvious algebra question math just isn't my strongest subject! Thanks.
1 solutions

Answer 287577 by josmiceli(9817) About Me  on 2011-02-12 11:27:43 (Show Source):
You can put this solution on YOUR website!
Your answer is correct. You got
cot%28pi%2F3%29+=+1%2Fsqrt%283%29
Now multiply top and bottom by sqrt%283%29%2Fsqrt%283%29
Notice that this doesn't change anything, since
sqrt%283%29%2Fsqrt%283%29+=+1%2F1
%281%2Fsqrt%283%29%29%2A%28sqrt%283%29%2Fsqrt%283%29%29+=+sqrt%283%29%2F3


Length-and-distance/408126: Line segment side AB has endpoints A (2, -3) and B (-4, 6). What are the coordinates of the midpoint of the side AB?
1. (-2, 3)
2. (-1, 1 1/2)
3. (-1, 3)
4. (3, 4 1/2)
1 solutions

Answer 287576 by josmiceli(9817) About Me  on 2011-02-12 11:21:22 (Show Source):
You can put this solution on YOUR website!
Find the midpoint of the x-coordinates, then the y-coordinates.
%282+%2B%28-4%29%29%2F2+=+-1
and
%28-3+%2B+6%29%2F2+=+3%2F2
I get (2) (-1, 3/2) as the answer


Inequalities/406080: Hi i have two questions, one dealing with inequalities. Im only in pre algebra and i dont understand. Can you please answer this and maybe i will understand?
Solve the following inequality:
2 < -8s
Now for the second question its a word problem having to do with feet per second? Another person asked this same math question, but the answer was wrong!
QUESTION : ACCORDING TO THE GUINNESS BOOK OF WORLD RECORDS, THE PEREGRINE FALCON HAS A RECORD DIVING SPEED OF 168 MILES PER HOUR. WRITE THIS SPEED PER SOCOND.
Thankyou! Please respond quick.
1 solutions

Answer 286666 by josmiceli(9817) About Me  on 2011-02-08 10:29:43 (Show Source):
You can put this solution on YOUR website!
Hi,
I'll explain this problem with a more simple problem that shows
the exact same idea.
1+%3E+-x
OK, what you want to find is x. What is the given inequality telling you?
If x+=+1
then 1+%3E+-1 true
-----------------
If x+=+0
then 1+%3E0 true
-----------------
If x+=+-1
then 1+%3E+1 not true
----------------
In fact, if x is -1, -2, -3, -4, or any minus number more negative than -1,
the inequality is not true. It is true for any number that is more positive than -1
That includes the negative fractions like -1/3, -1/4, -1/5, etc. and also the
positive fractions like 1/3, 1/4, etc. and then it is true for all the positive numbers,
1, 2, 3, 4, etc.
--------------
Now I still want to find x. The normal way to do this with an equality is to
divide both sides by -1
1%2F%28-1%29+%3E+%28-x%29%2F%28-1%29
plus divided by minus is minus and
minus divided by minus is plus, so
-1+%3E+x
and now just write this going from right to left
x+%3C+-1 this is the same thing
But what happened? I said the original inequality was true for all numbers
greater than -1, or, in other words, x+%3E+-1.
Now I divided both sides by -1, and the result is telling me just the opposite.
This leads to a general rule:
------------------------------------------------------
Whenever you divide both sides of an inequality by a minus quantity,
you must reverse the inequality sign when you are done.
Following this law:
1+%3E+-x
1%2F%28-1%29+%3C+%28-x%29%2F%28-1%29
-1+%3C+x
Now rewriting this from right to left:
x+%3E+-1
Notice I reversed the inequality sign, and it is now true.
----------------
So, to solve your problem:
2+%3C+-8s
2%2F%28-1%29+%3E+%28-8%2F-1%29%2As (I reversed the inequality sign)
-1%2F4+%3E+s
s+%3C+-1%2F4 (I just rewrote it going right to left)
This is true- try any number that is greater than or equal to -1%2F4,
and the inequality becomes false.
for example:
s+=+-1%2F10
2+%3C+-8%2A%28-1%2F10%29
20+%3C+8%2F10 not true
----------------
I hope all this helps and isn't too confusing.




Polynomials-and-rational-expressions/405860: college algebra - completing the square
would you help me finish this? I wasn't sure what factors to pick out from 196 so I choose 4 times 49. How do I choose what to use?
x^2-10x+24=0
x=-10+-sqrt((-10)^2-4(1)(24))/2(1))
x=10 +- sqrt((100-(-96))/2)
x=10 +-sqrt((196)/(2)
2sqrt(4(49))/2))
sqrt(2^2(49))/(2)
2+-sqrt49/2
2(1+-sqrt49/2)
1sqrt49
x=1sqrt49 right?
1 solutions

Answer 286586 by josmiceli(9817) About Me  on 2011-02-07 21:27:29 (Show Source):
You can put this solution on YOUR website!
x%5E2-10x%2B24=0
Here's how I do it:
x%5E2+-+10x+=+-24
Take 1/2 of the coefficient of x, square it, and add it
to both sides.
x%5E2+-+10x+%2B+%28-10%2F2%29%5E2+=+%28-10%2F2%29%5E2+-+24
x%5E2+-+10x+%2B+25+=+25+-+24
%28x+-+5%29%5E2+=+1
Take the square root of both sides
x+-+5+=+1
x+=+6
and, also
x+-+5+=+-1 (the other square root of 1)
x+=+4
from these, I get x-6+=+0 and x-4+=+0, so
The factors are
%28x+-+6%29%2A%28x+-+4%29


Graphs/405859: How Do I Graph: y < -1
1 solutions

Answer 286580 by josmiceli(9817) About Me  on 2011-02-07 21:17:28 (Show Source):
You can put this solution on YOUR website!
This is all the points below horizontal line through the y-intercept at y+=+-1.
The extra condition is that the points on the line not included
If the equation was y%3C=-1, then the points on the line
would also be included


Linear_Equations_And_Systems_Word_Problems/405851: A property tax on a house with an assessed value of $480,000 is $5760. Determine the property tax on a house with an assessed value of $600,000, assuming the same tax rate.
1 solutions

Answer 286577 by josmiceli(9817) About Me  on 2011-02-07 21:11:30 (Show Source):
You can put this solution on YOUR website!
The rate is 5760%2F480000+=+.00992
600000%2A+.00992+=+5949.96
The tax is $5,949.96


Equations/405834: Hello,
I need some help because I don't get what I am doing wrong. Here is the problem.
Find an equation of the line containing the given pair of points.
(-5,-9)(-1,-8)
The equation of the line in slope-intercept form is y=4/4x-33/4 (this is my answer)
The answer given is 1/4x-31/4.
Why? I don't get how they get 31/4.
Please help soon.
Sincerely
Demi
1 solutions

Answer 286566 by josmiceli(9817) About Me  on 2011-02-07 20:53:20 (Show Source):
You can put this solution on YOUR website!
Using the point-slope formula
%28y+-+%28-9%29%29+%2F+%28x+-+%28-5%29%29+=+%28-8+-+%28-9%29%29+%2F+%28-1+-+%28-5%29%29
%28y+%2B+9%29+%2F+%28x+%2B+5%29+=+%28-8+%2B+9%29+%2F+%28-1+%2B+5%29
%28y+%2B+9%29+%2F+%28x+%2B+5%29+=+1%2F4
y+%2B+9+=+%281%2F4%29%2A%28x+%2B+5%29
4y+%2B+36+=+x+%2B+5
4y+=+x+-+31
y+=+%281%2F4%29%2Ax+-+31%2F4 answer
check:
does the line include the given point?
(-1,-8)
-8+=+%281%2F4%29%2A%28-1%29+-+31%2F4
-32+=+-1+-+31
-32+=+-32
You can check the other point


Numbers_Word_Problems/405806: I am a two digit number with the sum of 13. I have a 9 in the tens place...I am
I am a two digit number with the sum of 7. I have a 0 in the ones place...I am
I am a two digit number with the sum of 1. I have an 8 in the ones place. I am
I am an even number less than 50 with the sum of 9. I am
I am a three digit number with a sum of 27. I am
My son is having problems trying to figure these out. Can you please help me understand how to do this so that I can help him understand.
Thanks
1 solutions

Answer 286558 by josmiceli(9817) About Me  on 2011-02-07 20:40:57 (Show Source):
You can put this solution on YOUR website!
I am a two digit number with the sum of 13. I have a 9 in the tens place
The number must be 94, because 9 + 4 = 13
-----------------------------------
I am a two digit number with the sum of 7. I have a 0 in the ones place
The number is 70, since 7 + 0 = 7
---------------------------
I am an even number less than 50 with the sum of 9
It's not 45, since that is an odd number
It could be 36, which is even
It can't be 27, which is odd
It could be 18, which is even
------------------------
I am a three digit number with a sum of 27
The number must be 999
There is no larger 3-digit number, and
any smaller number adds up to less than 27,
like 989, 9 + 8 + 9 = 26


Proportions/405681: Recently, 1 U.S. dollar was worth
0.69 English pound. If you
exchanged 500 English pounds, how
many dollars would you get?
1 solutions

Answer 286502 by josmiceli(9817) About Me  on 2011-02-07 17:45:15 (Show Source):
You can put this solution on YOUR website!
You are converting pounds to dollars
500 pounds x 1%2F.69 dollars/pound = 724.64 dollars


test/405673: The sum of three consecutive odd integers if the first integer is x
1 solutions

Answer 286494 by josmiceli(9817) About Me  on 2011-02-07 17:23:51 (Show Source):
You can put this solution on YOUR website!
The 1st integer is x
The numbers go odd, even, odd, even, etc.
so, the next odd number is x+%2B+2
and thr next odd integer is x+%2B+4
The sum is x+%2B+x+%2B+2+%2B+x+%2B+4+=+3x+%2B+6 answer
to check: suppose x+=+7
x+%2B+2+=+9
x+%2B+4+=+11
7+%2B+9+%2B+11+=+27
and
3x+%2B+6+=+3%2A7+%2B+6
21+%2B+6+=+27
OK


Mixture_Word_Problems/405382: How many liters of a 40% acid solution must be added to 12 liters of a 20% solution to obtain a 25% solution? Can you please show me how to work out this problem also:) Thanks.
1 solutions

Answer 286325 by josmiceli(9817) About Me  on 2011-02-06 23:20:26 (Show Source):
You can put this solution on YOUR website!
Let a = liters of 40% solution needed
given:
.2%2A12+=+2.4 liters of acid in 20% solution
.4a = liters of acid in 40% solution
------------------------------------------------
%28.4a+%2B+2.4%29%2F%28a+%2B+12%29+=+.25
.4a+%2B+2.4+=+.25%2A%28a+%2B+12%29
.4a+%2B+2.4+=+.25a+%2B+3
.15a+=+.6
15a+=+60
a+=+4
4 liters of 40% solution are needed
check answer:
%28.4%2A4+%2B+2.4%29%2F%284+%2B+12%29+=+.25
4%2F16+=+.25
.25+=+.25
OK


Miscellaneous_Word_Problems/405385: 170 is what percent of 20?
20 is what percent of 170?
1 solutions

Answer 286324 by josmiceli(9817) About Me  on 2011-02-06 23:12:38 (Show Source):
You can put this solution on YOUR website!
170+=+%28x%2F100%29%2A20
17000+=+20x
x+=+850
850%
-------------------
20+=+%28x%2F100%29%2A170
2000+=+170x
x+=+11.76
11.76%


Polynomials-and-rational-expressions/405384: factor each polynomial, if possible. if the polynomial cannot be factored, write prime. 4-28r+49r squared
1 solutions

Answer 286323 by josmiceli(9817) About Me  on 2011-02-06 23:06:11 (Show Source):
You can put this solution on YOUR website!
49r%5E2+-28r+%2B+4
I notice that if I say s+=+7r, then I can say
s%5E2+-+4s+%2B+4
This is obviously factored to
%28s+-+2%29%5E2
Now I can put it in terms of r
%287r+-+2%29%5E2
There are 2 factors, and they are both 7r+-+2


Probability-and-statistics/405121: Eight mathematics books and three chemistry books are to be placed on a shelf. In how many ways can this be done if the mathematics books are next to each other and the chemistry books are next to each other?
1 solutions

Answer 286206 by josmiceli(9817) About Me  on 2011-02-06 15:40:29 (Show Source):
You can put this solution on YOUR website!
There are 1%2A2%2A3%2A4%2A5%2A6%2A7%2A8+=+40320 possible ways to
arrange 8 math books
There are 1%2A2%2A3+=+6 ways to arrange 3 chem books
40320+%2B+6+=+40326
Also, the math books could be on the left, chem on the right
or the opposite way, so the answer is 2%2A40326+=+80652


Linear-systems/405113: Is (0, -2) a solution of 2x - 5y = 10?
1 solutions

Answer 286202 by josmiceli(9817) About Me  on 2011-02-06 15:25:16 (Show Source):
You can put this solution on YOUR website!
(0,-2) has the form (x,y), so
x+=+0
y+=+-2
Just plug these values into the equation
2x+-+5y+=+10
2%2A0+-+5%2A%28-2%29+=+10
10+=+10
Yes, the point (0,-2) is a solution


Word_Problems_With_Coins/405108: There are two times as many dimes as nickles, and the value of the dimes in $1.65 more than the value of the nickles. How many nickles and dimes total.
1 solutions

Answer 286199 by josmiceli(9817) About Me  on 2011-02-06 15:22:25 (Show Source):
You can put this solution on YOUR website!
Let n = number of nickels
Let d = number of dimes
given:
d+=+2n
10d++=+5n+%2B+165 (in cents)
By substitution:
10%2A2n+=+5n+%2B+165
20n+-+5n+=+165
15n+=+165
n+=+11
and
d+=+2n
d+=+22
There are 11 nickels and 22 dimes
check answer:
10d++=+5n+%2B+165
10%2A22+=+5%2A11+%2B+165
220+=+55+%2B+165
220+=+220
OK


Age_Word_Problems/405061: This problem has me thoroughly stumped:
"Mary is 3 years older than John. In three years John's age will be 4/5 of Mary's age. What are their ages now?"
1 solutions

Answer 286182 by josmiceli(9817) About Me  on 2011-02-06 14:07:23 (Show Source):
You can put this solution on YOUR website!
Let m = Mary's age now
Let j = John's age now
given:
(1) m+=+j+%2B+3
Next is an equation that compares their ages when they are both 3 yrs older
(2) j+%2B+3+=+%284%2F5%29%2A%28m+%2B+3%29
------------------------
(2) 5%2A%28j+%2B+3%29+=+4%2A%28m+%2B+3%29
(2) 5j+%2B+15+=+4m+%2B+12
(2) 4m+-+5j+=+3
and
(1) m+-+j+=+3
Multiply both sides by 5 and subtract
(2) from (1)
(1) 5m+-+5j+=+15
(2) -4m+%2B+5j+=+-3
m+=+12
and, from(1):
m+=+j+%2B+3
12+=+j+%2B+3
j+=+9
Mary is 12 and John is 9
check answer:
(2) j+%2B+3+=+%284%2F5%29%2A%28m+%2B+3%29
(2) 9+%2B+3+=+%284%2F5%29%2A%2812+%2B+3%29
(2) 12+=+%284%2F5%29%2A15
12+=+12
OK
and, also
(1) m+=+j+%2B+3
(1) 12+=+9+%2B+3
12+=+12
OK


Travel_Word_Problems/404852: “It took Peter sixteen more minutes to drive to work today than it did yesterday. Tomorrow he wants it to take five minutes less than yesterday so that his average drive time for the three days is no more than 30 minutes. How long did it take Peter to get to work each day?”


1 solutions

Answer 286111 by josmiceli(9817) About Me  on 2011-02-06 02:17:56 (Show Source):
You can put this solution on YOUR website!
Let t = time to drive yesterday
t+%2B+16 = today's time
t+-+5 = time he wants to drive tomorrow
The average time is:
%28t+%2B+t+%2B+16+%2B+t+-+5%29%2F3+%3C=+30
%283t+%2B+11%29%2F3+%3C=+30
+3t+%2B+11+%3C=+90
3t+%3C=+79
t+%3C=+79%2F3
t+%2B+16+%3C=+127%2F3
t+-+5+%3C=+64%2F3
The times are:
26 1/3 min, 42 1/3 min, and 21 1/3 min


Linear-systems/404857: Solve for unknown:
3x-4y=10
4x-3y=5
(I used the method of interchangeable coefficients but not getting the answer)
1 solutions

Answer 286109 by josmiceli(9817) About Me  on 2011-02-06 02:05:53 (Show Source):
You can put this solution on YOUR website!
3x+-+4y+=+10
4x+-+3y+=+5
I think I would multiply the top equation by -%283%2F4%29
-%289%2F4%29%2Ax+%2B+3y+=+-+15%2F2
4x+-+3y+=+5 (now add)
-%289%2F4%29%2Ax+%2B+4x+=+10%2F2+-+15%2F2
%2816%2F4+-+9%2F4%29%2Ax+=+-+5%2F2
%287%2F4%29%2Ax+=+-10%2F4
7x+=+-10
x+=+-10%2F7
Substitute this in the top equation:
-30%2F7+-+4y+=+70%2F7
-30+-+28y+=+70
28y+=+-100
y+=+-25%2F7
I'll check the 2nd equation:
4x+-+3y+=+5
4%28-10%2F7%29+-+3%28-25%2F7%29+=+5
-40%2F7+%2B+75%2F7+=+35%2F7
35%2F7+=+35%2F7
OK
You can check 1st



Miscellaneous_Word_Problems/404875: Hi I am needing some help with this word problem please.
A bathtub can be filled by the cold water facuet in 10 mins and by the hot water facuet in 12 mins. How long does it take to fill the bath tub if both facuets are open? My email address is wa_emily@yahoo.com
Thank you so much
1 solutions

Answer 286107 by josmiceli(9817) About Me  on 2011-02-06 01:52:23 (Show Source):
You can put this solution on YOUR website!
You are adding rate:
(1 tub filled w/cold faucet)/(min to fill tub) + (1 tub filled w/hot faucet)/ (min to fill tub) = (1 tub filled)/(x min with both faucets open)
1%2F10+%2B+1%2F12+=+1%2Fx
Multiply both sides by 60x
6x+%2B+5x+=+60
11x+=+60
x+=+60%2F11 min


Miscellaneous_Word_Problems/404877: Hi I am needing some help on this word problem please.
A sink can be filled by the cold water facuet in 3 mins. The drain can empty a full sink in 4 mins. If the sink is empty and both the cold water facuet and the drain are open, how long will it take the sink to overflow.
Thank you so much
1 solutions

Answer 286104 by josmiceli(9817) About Me  on 2011-02-06 01:44:37 (Show Source):
You can put this solution on YOUR website!
This is a rate problem.
Add the rates to get the resulting rate.
Filling the sink in a (+) rate
Emptying the sink is a (-) rate
The best way to understand it is
to express solution in words.
(1 sink filled)/(minutes to fill sink) - (1 sink drained)/(minutes to drain sink) = (1 sink filled)/(minutes to fill sink w/drain and faucet open)
1%2F3+-+1%2F4+=+1%2Fx
Multiply both sides by 12x
4x+-+3x+=+12
x+=+12
It takes 12 min for the sink to overflow with faucet
and drain open


Linear-equations/404878: Write an equation for a line that passes through (-4.5) and (0,-2)
1 solutions

Answer 286102 by josmiceli(9817) About Me  on 2011-02-06 01:33:59 (Show Source):
You can put this solution on YOUR website!
%28y+-+%28-2%29%29%2F%28x+-+0%29+=+%285+-+%28-2%29%29%2F%28-4+-+0%29
%28y+%2B+2%29%2F+x+=++-7+%2F+4
+4%2A%28y+%2B+2%29+=+-7x
4y+%2B+8+=+-7x
4y+=+-7x+-+8
y+=+-%287%2F4%29%2Ax+-+2
Does it go through (-4,5)?
5+=+-%287%2F4%29%2A%28-4%29+-+2
5+=+7+-+2
5+=+5
OK
You can check the other point


Travel_Word_Problems/404872: A person travels by car from one city to an-
other. She drives for 24.9 min at 74 km/h,
10.4 min at 105 km/h, 42.6 min at 45.9 km/h,
and spends 19.1 min along the way eating
lunch and buying gas.
Determine the distance between the cities
along this route.
Answer in units of km.
1 solutions

Answer 286100 by josmiceli(9817) About Me  on 2011-02-06 01:27:57 (Show Source):
You can put this solution on YOUR website!
If the person goes from 1 city to another,
you only care about distances traveled, and
not time spent while not traveling.
To get distances:
d1 = %2824.9%2F60%29%2A74
d2 = %2810.4%2F60%29%2A105
d3 = %2842.6%2F60%29%2A45.9
Add d1 + d2 + d3