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Linear_Equations_And_Systems_Word_Problems/99758: Lopez spent 1/3 of his vaction money for travel and 2/5 of his vacation money for lodging. He spent $1100 for travel and lodging. What is the total amount of money he spent on his vacation?
I know x + y = 1100
1/3x = 2/5y = (not sure from this point!!!) 1 solutions
Answer 72630 by edjones(7569) on 2007-09-22 21:51:22 (Show Source):
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Length-and-distance/99730: O is the midpoint of NP; NP = 3x + 4y , NO = 2x + 3y - 5, OP = 5x - y, FIND the lengths of NO,OP, and NP. May you please show work also.
N-----O-----P 1 solutions
Answer 72603 by edjones(7569) on 2007-09-22 17:26:15 (Show Source):
You can put this solution on YOUR website!A) 2x+3y-5=5x-y
subtract 5x and add y to each side: -3x+4y-5=0
add 5 to each side: -3x+4y=5
B) 3x+4y=2(2x+3y-5)
3x+4y=4x+6y-10
subtract 4 and 6y from each side: -x-2y=-10
| Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition |
Lets start with the given system of linear equations


In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).
So lets eliminate x. In order to do that, we need to have both x coefficients that are equal but have opposite signs (for instance 2 and -2 are equal but have opposite signs). This way they will add to zero.
So to make the x coefficients equal but opposite, we need to multiply both x coefficients by some number to get them to an equal number. So if we wanted to get -1 and -3 to some equal number, we could try to get them to the LCM.
Since the LCM of -1 and -3 is 3, we need to multiply both sides of the top equation by -3 and multiply both sides of the bottom equation by 1 like this:
Multiply the top equation (both sides) by -3
Multiply the bottom equation (both sides) by 1
So after multiplying we get this:


Notice how 3 and -3 add to zero (ie )
Now add the equations together. In order to add 2 equations, group like terms and combine them


Notice the x coefficients add to zero and cancel out. This means we've eliminated x altogether.
So after adding and canceling out the x terms we're left with:

Divide both sides by to solve for y
Reduce
Now plug this answer into the top equation to solve for x
Plug in 
Multiply
Reduce
Subtract from both sides
Combine the terms on the right side
Multiply both sides by . This will cancel out on the left side.
Multiply the terms on the right side
So our answer is
, 
which also looks like
( , )
Notice if we graph the equations (if you need help with graphing, check out this solver)


we get
graph of (red) (green) (hint: you may have to solve for y to graph these) and the intersection of the lines (blue circle).
and we can see that the two equations intersect at ( , ). This verifies our answer. |
Check:
NO) 6+10.5-5=11.5
OP) 15-3.5=11.5
NP) 9+14=23
11.5+11.5=23
Ed
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Triangles/99722: how can i create a rectangle with two sides that each measure 2 centimeters, and whose area is exactly 13 cm2? 1 solutions
Answer 72598 by edjones(7569) on 2007-09-22 16:02:12 (Show Source):
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Linear-systems/99704: three no. are in the ratio 3:4:5 if the sum of the largest and the smallest equal the sum of the third and 52, find the numbers. 1 solutions
Answer 72597 by edjones(7569) on 2007-09-22 15:51:09 (Show Source):
You can put this solution on YOUR website!sum of the largest and the smallest equal the sum of the third and 52, find the numbers.
the new triangle must have the sides proportional to 3:4:5
let x= the multiple of each side to make a side of the new triangle.
3x+5x=4x+52
3x+5x-4x=52
4x=52
divide 4 into each side: x=13
13*3=39
13*4=52
13*5=65
Check:
39+65=52+52
104=104
Ed
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Miscellaneous_Word_Problems/99724: Please help! This word problem has me stumped. An airplane covered 15 miles of its route while decreasing its altitude by 18,000 feet. Find the slope of the airplane's line of descent. Round to the nearest hundredth. I just don't think I have enough information to get a solution. 1 solutions
Answer 72596 by edjones(7569) on 2007-09-22 15:39:48 (Show Source):
You can put this solution on YOUR website!18,000/5280=3.41 mi
I drew a diagram on graph paper.
I had the plane at x=0 y=3.41 at the start of decent and at x=-15 y=0 at the end.
this gives us 2 points. (0,3.41) and (-15,0)
slope= change in y/change in x=(3.41-0)/0-(-15)=3.41/15=.227
Ed
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Triangles/99712: Hi my name is Tim and I have a question about graphing triangles.
14. The vertices of a right triangle are (-12, 8), (24, 8), and (24, -7). Find the length of the hypotenuse of the triangle (hypotenuse = side opposite the right angle).
1 solutions
Answer 72594 by edjones(7569) on 2007-09-22 15:22:39 (Show Source):
You can put this solution on YOUR website!you have to use the distance formula:  on one of the sides.
if you put the points on graph paper it becomes obvious that 36 and 15 are the lengths of 2 of the sides. and the 3rd side is the hypotenuse.
now you can use the formula above or the pythagorean theorum: a^2+b^2=c^2
36^2+15^2=c^2
1296+225=1521
sqrt(1521)=39 (one way)
 (another way)
Ed
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Polynomials-and-rational-expressions/99715: i did this problem but still am having trouble can you please slove it for me with the work shown thank you
y^2-11y+30=
this is the work ive done so far:
y^2-6y-5y+30=0
y(y-6)-5(y-6)=0
(y-5)(y-6)=0
product =30y^2
sum= 11y
-6yx-5y=30
-6y-5y=+1y
1 solutions
Answer 72591 by edjones(7569) on 2007-09-22 14:54:42 (Show Source):
You can put this solution on YOUR website!y^2-11y+30=0
factor: (y-5)(y-6)=0
y=5 or y=6
comments:
your initial equation lacked a zero after the = sign.
Your 3rd try led to the correct answer.
the rest are bad algebra.
practice factoring. get it down in your mind.
Ed
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Problems-with-consecutive-odd-even-integers/99717: While Michelle sat observing birds at a bird feeder, one fourth of the birds flew away when they were startled by a noise. Two birds left the feeder to go to another stationed a few feet away. Three more birds flew into the branches of a nearby tree. Four birds remained at the feeder. How many birds were at the feeder initially? 1 solutions
Answer 72586 by edjones(7569) on 2007-09-22 14:34:38 (Show Source):
You can put this solution on YOUR website!let x=number of birds initially
x-x/4-2-3=4
multiply 4 times each side: 4x-x-8-12=16
3x-20=16
add 20 to each side: 3x=36
divide 3 into each side: x=12 bird originally at the feeder.
Check:
12-12/4-2-3=4
12-3-2-3=4 true
Ed
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Quadratic_Equations/99713: Could you please help me solve this equation....The directions say Solve Each Equation by making an appropriate solution...Here is the problem:
x-13√x+40=0
√=Square root...Didn't know if that looked like one so I was telling you what it was... 1 solutions
Answer 72584 by edjones(7569) on 2007-09-22 14:24:46 (Show Source):
You can put this solution on YOUR website!

square each side: x^2+80x+1600=169x
x^2-89x+1600=0
factor: (x-64)(x-25)=0
x=64 or x=25
check:
64-13sqrt(64)+40=0...64-13*8+40=0...64-104+40=0 true
25-13sqrt(25)+40=0...25-13*5+40=0...25-65+40=0 true
Ed
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Miscellaneous_Word_Problems/99698: A home purchased for $300,000 depreciated 8% over a 1-year period. What was the
value of the home after at the end of the year?
A) $278,000
B) $272,000
C) $274,000
D) $276,000
I came up with $276,000 is that correct?
1 solutions
Answer 72578 by edjones(7569) on 2007-09-22 13:22:22 (Show Source):
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Finance/99648: Can you help me simplify the following leaving the answer in index form please.
4m^8x2m^2/6m^5 or 4mx10 to the eight x 2m squared divided by 6m to the power of 5 1 solutions
Answer 72501 by edjones(7569) on 2007-09-21 20:42:24 (Show Source):
You can put this solution on YOUR website!add the exponents when multiplying like numbers.
subtract the exponents when dividing like numbers.
4m^8x2m^2/6m^5
8x^10/6m^5=4x^5/3
Ed
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Triangles/99635: Could someone please show me how to get the altitude of a triangle? I cant seem to remember the formula to solve. Please help me.
Side A 13
Side B 13
Bottom 10
1 solutions
Answer 72490 by edjones(7569) on 2007-09-21 19:50:32 (Show Source):
You can put this solution on YOUR website!The altitude divides the isoscoles triangle into 2 equal right triangles.
let a=altitude b=10/2=5 c=13
a^2+b^2=c^2
5^2+a^2=13^2
a^2=169-25=144
altitude=12
Ed
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Exponents/99524: the area of aquare field is 60025 m. square. A man cycles along its boundary at 18 km/hr. I how much time will he return at the starting point. 1 solutions
Answer 72392 by edjones(7569) on 2007-09-21 00:50:58 (Show Source):
You can put this solution on YOUR website!t=time s=speed d=distance
 m =.245 km (1 side of the field)
perimeter = 4*.245=.980 km
t=d/s
t=.980/18=49/900 hr
49/900*60=49/15 min= 3 min 16 sec
Ed
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