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What is the y- intercept of this function?
My ans is (5,0)
and what is the zero's of this parabola?
My ans is (0,-1),(0,-5)
am I correct?
1 solutions
Answer 34246 by rapaljer(4667) on 2006-09-09 08:50:25 (Show Source):
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Geometric_formulas/51300: I have tried this one and cannot figure it out. I have tried versions of the Pythagorean Theorem. Please Help! Two posts, one 12 meters high and the other 21 meters high, are 30 meters apart. A single wire runs from the top of the first post to the ground and from the ground to the top of the second post. The wire is attached to the ground at a distance of x units from the first post. What is a function representation that states the total length of the wire? 1 solutions
Answer 34245 by rapaljer(4667) on 2006-09-09 08:26:52 (Show Source):
You can put this solution on YOUR website!You have two right triangles, in which the two poles are the vertical legs of the triangles, and the length of the wire is the sum of the two hypotenuses (or would that be hypotenii???). Since the distance between the poles is 30 meters, let x= distance from first pole to the point where the wire touches the ground, and 30-x = distance from this point on the ground to the base of the second pole.
By Theorem of Pythagoras, the length of the wire from the top of the first pole to the ground is  , and the distance from the top of the second pole to the ground is  . The total length of the wire, is the sum of these radicals
It doesn't simplify much:
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Quadratic_Equations/51308: This question is from textbook
I am using the quadratic formula on 3x^2 = 11x + 4; 3x^2 - 11x + 4 = 0; 3x^2 - 11x - 4 = -2; I have to convert the 5.5 to a fraction, but I am confused. The answer is 1/3,-4 or the other way around (I think). I need an assist please. 1 solutions
Answer 34238 by rapaljer(4667) on 2006-09-09 01:22:20 (Show Source):
You can put this solution on YOUR website!I'm confused too!! You have three different quadratic equations, and I don't see how any of them relate to changing 5.5 to a fraction.
However, the first equation is
 , which becomes
 , which factors into
 or
 or  .
This works very well by factoring, so you don't need the quadratic formula, unless you specifically wanted to do it by quadratic formula. In this case, algebra.com has a "pluggable solver" that looks like this:
| Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc) |
Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.
First, we need to compute the discriminant : .
Discriminant d=169 is greater than zero. That means that there are two solutions: .


Quadratic expression can be factored:

Again, the answer is: 4, -0.333333333333333.
Here's your graph:
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Coordinate-system/51267: This question is from textbook Beginning Algebra
For this question, we must find the revenue from the sale of x items given by R=50x. Does this ask to graph the equation only or do I need to solve this for x. And if so, how do I do it? 1 solutions
Answer 34237 by rapaljer(4667) on 2006-09-09 01:04:33 (Show Source):
You can put this solution on YOUR website!You can't solve for x unless they give you the value of R. If you are to graph it, then it is a VERY steep graph with the y intercept (actually the R intercept) of 0, and a slope of 50 over 1. Like this:
Look closely at this graph. The graph is so steep you can hardly see it!!
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Linear-systems/51233: Exercise 2.2 #19 on page 97
Solve the system for p and q in terms of x and y. Explain how you could check your solution and perform the check.
x=2+p-2q
y=3-p+3q
I've been all over the chapter and couldn't find anything remotely helpful for this. Please help!!! 1 solutions
Answer 34176 by rapaljer(4667) on 2006-09-08 08:05:43 (Show Source):
You can put this solution on YOUR website!It may be helpful to find a way to eliminate the p, and then eliminate the q, and write two equations, one for p and one for q.
First, if you add the two equations together, you can eliminate the p, and get
x=2+p-2q
y=3-p+3q
x+y = 5 + q, so q = x+y-5
Second, to eliminate the q, multiply both sides of the first equation by 3, and the second equation by 2:
3(x)=3(2+p-2q)
2(y)=2(3-p+3q)
3x= 6 +3p-6q
2y = 6-2p+6q
3x+2y = 12 +p, so p=3x+2y - 12
There you have it:
p=3x+2y-12
q=x+y-5
I have no idea how to check this, unless you solve for x and y to see if you come back with the same equations that you started with. It looks like Linear Algebra to me. Hey, I gotta go to work this morning!!
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Linear_Equations_And_Systems_Word_Problems/51235: This question is from textbook algebra 2 explorations and applycations
I needed help with setting up the eqations for this problem:
27. A bread maker costs $199. The ingredients and electricity to make one loaf of bread with the machine cost $.79. A loaf of bread of similar quality costs $1.59 at a grocery store.
a.)write two equations giving the total cost "C" in terms of the number of loavs "l" made or purchased for each situation.
b.) Solve the system of equations to find the number of loaves of bread you have to make before the breadmakerpays for itself. 1 solutions
Answer 34175 by rapaljer(4667) on 2006-09-08 07:52:35 (Show Source):
You can put this solution on YOUR website!Let L = number of loaves of bread.
C = total cost of the loaves.
Machine cost:
C = 199 + .79L
Store cost:
C = 1.59L
199 +.79L = 1.59L
Subtract .79L from each side:
199+.79L -.79L = 1.59L - .79L
199=.8L
Divide both sides by .8:
Answer: On the 160th loaf of bread, the machine becomes the lesser cost.
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Exponential-and-logarithmic-functions/51141: i dont realli no how 2 word this...but wats it mean if theres an exponent before a sq. root (not after)...u multiply the sq. root by the exponent?
1 solutions
Answer 34168 by rapaljer(4667) on 2006-09-08 01:16:55 (Show Source):
You can put this solution on YOUR website!You are probably talking about a cube root, fourth root, etc.
For example,  is a cube root. It means "what number can you raise to the third power and get 27?" Of course, the answer is 3, because  .
As another example,  is a fourth root. It means "what number can you raise to the fourth power and get 16?" Of course, the answer is 2, because  .
I have a complete explanation of this as a Lesson Plan in algebra.com under "Square-cubic-other-roots." Also, see my own website by clicking on my tutor name "rapaljer" anywhere in algebra.com, then go to Basic Algebra, the look for "Samples from Basic Algebra: One Step at a Time", then Chapter 5, which is a complete explanation of radicals.
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Functions/51184: If f(x) = 7x^5 - 3, then f ^-1(x) =
a. [(x + 7)/5]1/3
b. [(x + 3)/5]1/7
c. [(x + 5)/7]1/3
d. [(x + 7)/3]1/5
e. [(x + 3)/7]1/5
f. [(x + 5)/3]1/7
g. none of these 1 solutions
Answer 34166 by rapaljer(4667) on 2006-09-08 01:05:49 (Show Source):
You can put this solution on YOUR website!The way to find an inverse function, you begin with an xy equation:  .
There are two steps:
1. Interchange the x and y; and
2. Solve for y.
Given:
Step 1:
Step 2: Solve for y.
Add +3 to each side:
Divide by 7:
Take the 5th root of each side or raise both sides of the equation to the  power
It looks like e) is the correct answer!
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Graphs/51186: Determine whether the relation is a function. If it is a function, state its domain and range.
{(–8, 7), (–5, –4), (–3, 3), (–3, 6)}
a. Domain: {7, –4, 3, 6}; Range: {–8, –5, –3}
b. Domain: {–8, –5, –3}; Range: {7, –4,3, 6}
c. Domain: {–8, –5, –3}; Range: 11
d. The relation is not a function. 1 solutions
Answer 34164 by rapaljer(4667) on 2006-09-08 00:55:56 (Show Source):
You can put this solution on YOUR website!Given: {(–8, 7), (–5, –4), (–3, 3), (–3, 6)}
First, the Domain is the set of all x values, which are the first numbers in each pair: {-8,-5,-3}.
Second, the Range is the set of all y values, which are the second numbers in each pair: {7,-4,3,6}
Third, it is NOT a function, since two points have the same x coordinate: (-3,3) and (-3,6).
Now,
a. Domain: {7, –4, 3, 6}; Range: {–8, –5, –3}
Domain and range are backwards. False
b. Domain: {–8, –5, –3}; Range: {7, –4,3, 6}
Both are correct!! True
c. Domain: {–8, –5, –3}; Range: 11
Domain is correct, but range is wrong. False
d. The relation is not a function.
This is true.
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Graphs/51199: Find two quadrants in which there are no points on the graph of xy = 12.
a. I & II
b. I & III
c. I & IV
d. II & III
e. II & IV
f. III & IV
g. Al of these have points in at least three quadrants. 1 solutions
Answer 34162 by rapaljer(4667) on 2006-09-08 00:46:24 (Show Source):
You can put this solution on YOUR website!Since you have a product of x times y equal to a positive number, this means that either x and y are both positive (Quadrant I) or they are both negative (Quadrant III). Therefore all the points are in Q I and III, so there are NO points in Q II and IV. Final answer is e).
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Graphs/51201: Determine if the point (–5, 3) lies in the viewing window defined by Xmin = –3, Xmax = 12, Ymin = –6, Ymax = 15.
a. Yes
b. No 1 solutions
Answer 34161 by rapaljer(4667) on 2006-09-08 00:43:35 (Show Source):
You can put this solution on YOUR website!No! The x value is -5, which is NOT between -3 and 12. The value of y is 3, which is between -6 and 15, but the x value is not, so it will not be in the viewing window.
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Quadratic_Equations/51207: This question is from textbook Beginning Algebra
I'm lost here, can someone help?
Find the axis of symmetry.
y=x^2+6x+5 1 solutions
Answer 34160 by rapaljer(4667) on 2006-09-08 00:41:16 (Show Source):
You can put this solution on YOUR website!This is a parabola that opens upward, and the axis of symmetry for such a graph in the form of  will always be  .
In the case of  , the axis of symmetry will be
The graph looks like this, using a graphing calculator, or this fantastic "algebra.com" calculator:
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Inequalities/51226: 5/2x-3 = 3/x-5
no idea how to work it out 1 solutions
Answer 34159 by rapaljer(4667) on 2006-09-08 00:34:21 (Show Source):
You can put this solution on YOUR website!Anytime you have a fraction equal to a fraction, like this:  , remember that
 means that
 means that
Now, 5x-25 =6x - 9
Subtract 5x from each side to get all the x terms on the right side:
5x-5x -25= 6x-5x-9
-25 = x-9
Next, add +9 to each side:
-25+9 = x-9+9
-16=x
Check by substituting back into the original equation:
 It checks!!
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logarithm/50915: Hi, I have a multiple choice question and i'm stuck between the two answers.
I have ln (x\square root of yz) =
either lnx - 1\2 (ln y - ln z)
or ln x - 1\2 (ln y + ln z).
I have got as far as ln x - square root ln y SOMETHING ln z
I am just not sure whether the SOMETHING should be plus or minus sign.
thanks for your help. 1 solutions
Answer 33936 by rapaljer(4667) on 2006-09-06 01:17:29 (Show Source):
You can put this solution on YOUR website!The ln of a product is the SUM of the logs, so use the positive. The negative is still outside the parentheses.
I have ln (x/square root of yz) =
ln x - 1/2 (ln y + ln z).
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logarithm/50916: Hi, the following question has me a little stumped...
it is solve for x
e^2in(2x)
does this then become e^(2x)squared??
not quite sure what to do with this question.
thanks. 1 solutions
Answer 33935 by rapaljer(4667) on 2006-09-06 01:13:17 (Show Source):
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Linear-systems/50913: Hi, I have to determine the linear function f(t) with slope -1 and f(2)= -1.
I have done slope -1 and (2, -1).
form f(x) =ax+b
a= -1
f(x) = -1
Since f(2)=1
f(2)= -1(2)+b
2=-2+b
2+2=b
4=b
f(t) = -1t+4
Is this even remotely on the right track??
thanks for your time! 1 solutions
Answer 33933 by rapaljer(4667) on 2006-09-06 01:05:41 (Show Source):
You can put this solution on YOUR website!You are almost right. You made a couple of very small errors, which I have corrected below for you.
I have done slope -1 and (2, -1).
form f(x) =ax+b
a= -1
f(x) = -1
Since f(2)=-1
f(2)= -1(2)+b
-1=-2+b
-1+2=b
1=b
f(t) = -1t+1
Now, check it! The slope is indeed -1.
f(2)= -1(2) + 1 = -2 +1 = -1, as it should be.
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Linear-equations/50686: How do you use a graphing calculator to graph the following equation:
x2-11x+18. I am assuming by X2 it means x to the second power. 1 solutions
Answer 33756 by rapaljer(4667) on 2006-09-04 08:04:16 (Show Source):
You can put this solution on YOUR website!Notice that there are five buttons across the top of the calculator. The first one is "y=" and the last one is "GRAPH". Start with the "y=" button. This opens up a whole screen full of y1=, y2=, y3=, etc. Next, you need to find the x-variable button, which is the second button down in the second column. This button actually says something that looks like "x,t,0,n". Press this button to get "x". To get the "squared" you can either press the x^2 button in the first column, or you can press the "^2" buttons. Then finish typing in the equation with a "minus 11 x + 18".
After you get that all typed in, press the last button across the top that says "GRAPH", and it should graph a parabola. See my handout on my website, since you may want to adjust the window to see it better.
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Linear-equations/50687: I have a TI84 plus graphing calculator> Could someone please explain to me how to use it in regards to graphing linear equations Thanks 1 solutions
Answer 33741 by rapaljer(4667) on 2006-09-04 01:25:32 (Show Source):
You can put this solution on YOUR website!You need to see my handout on the TI 84 graphing calculator. It's on my website, which you can find by clicking on my tutor name "rapaljer" anywhere in algebra.com. Then look for the page on "Calculator Handouts and Websites". My handout was so large I had to place it in three sections, and you will need the second of these three for graphing. It's really too much to do right here. Let me know if you need help with this. I won't have access to my office Email until Tuesday.
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expressions/50554: f(x) = (1 + x)/x
g(x) = 1/(1 - x)
h(x) = 1/(1 + x)
If so, (g o h)(x) =
a. x
b. 2 - x
c. -x
d. x/(2x + 1)
e. (1 - x)/(2 - x)
f. (1 + x)/x
g. (2 - x)/(1 - x)
h. (1 - x)/x
i. 2 + x
j. none of these 1 solutions
Answer 33740 by rapaljer(4667) on 2006-09-04 01:19:33 (Show Source):
You can put this solution on YOUR website!g(x) = 1/(1 - x)
h(x) = 1/(1 + x)
(g o h)(x) = g[ f(x) ]
g[ f(x) ] =
This looks a LOT worse than it really is!! It's a complex fraction, and I have a LOT of these worked out on my Math in Living Color pages of my website! I'm more comfortable in that format, and they are in "Living Color"!
Multiply both numerator and denominator by the LCD which is (1+x).
g[ f(x) ] =
g[ f(x) ] = 
g[ f(x) ] = 
g[ f(x) ] =  , which is the f) answer.
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Miscellaneous_Word_Problems/50667: The sum of two numbers is 130. One number is 46 times more than 1/2 the other number. What are the numbers?
Boy do I hate word problems. I can never seem to make sense out of them.
Matt 1 solutions
Answer 33739 by rapaljer(4667) on 2006-09-04 01:03:47 (Show Source):
You can put this solution on YOUR website!Let x = first number
and y = second number
Now, you need to write two equations since there are two unknowns.
The sum of two numbers is 130.
x+y = 130
One number is 46 times more than 1/2 the other number.
x= 1/2*y+46
If you don't like this equation because of the fraction, just multiply both sides by 2:
2x = y + 92 or 2x-y = 92
There, now it's not a word problem any more. It's solving two equations with two unknowns!!
x+ y = 130
2x -y = 92
Just add the two equations together:
3x= 222
x=74
Now, x + y = 130
so, 74 + y = 130
y=56
Check in the second equation:
x=1/2*y +46
74=1/2*56 + 46
74=28 + 46
It checks!!
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Graphs/50652: Dear Tutor,
Please help me with this problem..thanks!
Why is 2y+7x=-3 considered a line? We were asked in multiple choice form, and I figured this equation was a line by process of elimination but I would like to know why.
Thank You,
student in need 1 solutions
Answer 33737 by rapaljer(4667) on 2006-09-04 00:44:11 (Show Source):
You can put this solution on YOUR website!Any equation that is in the form of a number times x plus or minus a number times y equal to a number term will ALWAYS be a straight line. This form Ax+By=C is called the standard form of a line.
Also, any equation in the form of y = mx + b (called the slope-intercept form of a line) is also a straight line.
It's when you get x^2 or y^2 or division by x or y, like y = 12/x, etc. Then this is NOT a straight line.
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logarithm/50654: Hi, I have a question that is assume log4=.6021 determine log1\16. I know I can do this on the calculator and find log 1/16 is -1.2041, but that gives me no understanding of the problem. Is there a way to do working out to come to the solution??? thanks very much. 1 solutions
Answer 33736 by rapaljer(4667) on 2006-09-04 00:38:52 (Show Source):
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Equations/50656: 8*k^2+5*k=2*k^2+4
Thanks for the help,
Chris 1 solutions
Answer 33735 by rapaljer(4667) on 2006-09-04 00:31:56 (Show Source):
You can put this solution on YOUR website!Set the equation equal to zero:
8k^2+5k=2k^2+4
8k^2 -2k^2 + 5k -4 = 2k^2 + 4 - 2k^2- 4
6k^2 + 5k - 4 = 0
Factoring this trinomial is the hard part!! Try this combination:
6k^2 + 5k - 4 = 0
(3k + 4 )(2k - 1)= 0
3k = -4 or 2k = 1
k= -4/3 or k = 1/2
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Equations/50657: x^3-x^2+4*x-4=0
thanks a million:) 1 solutions
Answer 33734 by rapaljer(4667) on 2006-09-04 00:24:16 (Show Source):
You can put this solution on YOUR website!This is factoring by grouping. Group the first two and last two terms together.
Notice that there is a common factor of (x-1):
 or
Are you solving with complex numbers or real numbers only? If real numbers only, then the only answer you have to worry about is x=1. End of problem, since real numbers squared cannot equal a negative.
However, if complex numbers are allowed, then
 gives two solutions:
 ,
 ,  in addition to  .
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Equations/50682: solve:
x^3-x^2+4*x-4=0
thanks,
chris 1 solutions
Answer 33730 by rapaljer(4667) on 2006-09-03 22:30:54 (Show Source):
You can put this solution on YOUR website!This is factoring by grouping. Group the first two and last two terms together.
Notice that there is a common factor of (x-1):
 or
Are you solving with complex numbers or real numbers only? If real numbers only, then the only answer you have to worry about is x=1. End of problem, since real numbers squared cannot equal a negative.
However, if complex numbers are allowed, then
 gives two solutions:
 ,
 ,  in addition to  .
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