Questions on Algebra: Expressions involving variables, substitution answered by real tutors!

Tutors Answer Your Questions about Expressions-with-variables (FREE)

Question 180171: The sum of Nora's age and her grandmother's age is 71. Four times Nora's age is 6 less than her grandmother's age. Find their ages.
Click here to see answer by eperette(173)

Question 180228: Solve for y:
-2y + x - 4= 3y - 2x
what is y?
Click here to see answer by eperette(173)

Question 180242: Restriction on variable in a denominator
If the expression:
5z+5/6z+7
is to make sense, the values that can take must be restricted. State the restriction on
Click here to see answer by solver91311(16897)

Question 180227: Use the substitution method to solve the linear system
13. 3x-y = -2
y = 2x+3

Click here to see answer by solver91311(16897)

Question 180270: x+5(squarerootx)-10=2(squarerootx)
Click here to see answer by Earlsdon(6287)

Question 180326: Can you please help me solve this problem?!!?
The directions say: solve the equation by making the appropriate substitution.
Here is what I have so far....but I am stuck.

At this point I wasn't sure. Do I use the quadratic formula??? I tried that but just got confused. Please help. Thanks.
Click here to see answer by Alan3354(30993)

Question 180346: can you please help me solve the following: (((In the equation ax^2+bx+c=0, the value of b^2-4ac is called the___________of the quardratic equation. What does this value tell you about the real roots of the equation?)))
Click here to see answer by Alan3354(30993)

Question 180350: can you please help me solve the following: (((x varies directly as the square of s and inversely as t. How does x change when s is doubled? When both s and t are doubled?)))
Click here to see answer by stanbon(57361)

Question 180349: can you please help me answer the following: (((The distance an object falls is directly proportional to the square of the time it has been falling. After 6 seconds it has fallen 1296 feet. How long will it take to fall 2304 feet? )))
Click here to see answer by stanbon(57361)

Question 180348: can you please help me solve the following: (((How many x-intercepts the parabola has and wheather its vertex lies above or below or on the x-axis, y=-x^2+2x-1)))
Click here to see answer by stanbon(57361)

Question 180347: can you please help me solve the following: (((How many x-intercepts the parabola has and wheather its vertex lies above or below or on the x-axis, y=x^2-5x+6)))
Click here to see answer by Mathtut(3670)

Question 180345: can you please help me use the quadratic formula to solve the following and leave irrational roots in the simplest radical form: (((2x^2-3x+1=0)))
Click here to see answer by Mathtut(3670)

Question 180484: 5 times x - 16 = 50
I have tried to solve this one but I keep getting stuck, so I must be doing something wrong. If you could show your work it would be really helpful.
Thank you
Click here to see answer by checkley77(12569)

Question 180513: 5x-y=-18
4x+2y=92
These are both the same problem.I don't get how to do these problems.Could you explain to me how to do this type of problem please?
Click here to see answer by Alan3354(30993)

Question 180542:
Click here to see answer by Mathtut(3670)

Question 180481: 2 OVER x =
(The mixed number is the numerator and the x is the denominator.) I'm not sure how to solve this, the fraction with the mixed number as the numerator has got me confused. It would really help me if you could show your work.
Thank you
Click here to see answer by stanbon(57361)

Question 180587: 15) f(x) = x + 4
a. f(5) =
b. f(–7) =
c. f(0) =

16) f(x) = 6x + 5
a. f(12) =
b. f(–1/2) =
c. f(0) =

17) h(x) = x2 – 4x + 5
a. h(4) =
b. h(–4) =
c. h(0) =

Click here to see answer by Mathtut(3670)

Question 180613: Find (-8x^2y^3-3xy^2)+(5x^2y^3-xy^2)
Click here to see answer by Mathtut(3670)

Question 180596: I have anquestion, when I put an equation in the solver, do I use * for X always on any kind of problem? and a / for division? Thanks
Click here to see answer by user_dude2008(1861)

Question 180801: X^2 + 3x -15
Click here to see answer by jim_thompson5910(28595)

Question 180841: Driving marathon. Felix drove 800 miles in x hours on Monday.
a) Write a rational expression for his average speed.
b) On Tuesday he drove for 6 hours at the same average speed. Write a rational expression for his distance on Tuesday.

Click here to see answer by jim_thompson5910(28595)

Question 181016: Complementary angles are such that one angle whose sum is 90 degress. Two complementary angles are such that one angle is 6 degress more than five times the other. Find the measures of the angle.

Click here to see answer by stanbon(57361)

Question 181098: What is the formula to the elimination method?
x+y= 10
x-y= 2
Click here to see answer by Mathtut(3670)

Question 181097: What is the formula to the substitution method?
y=2x
2x+y= -12
Click here to see answer by Mathtut(3670)

Question 181211: Solve the system of equations by substitution.
3y-4x=-1
y-5x=-15
I worked it out to (4,5). Am I right?
Click here to see answer by Alan3354(30993)

Question 181211: Solve the system of equations by substitution.
3y-4x=-1
y-5x=-15
I worked it out to (4,5). Am I right?
Click here to see answer by HyperBrain(694)

Question 181216: A baker is making pastries to sell at a fair. A small pastry costs $1.50 to prepare. A large pastry costs $2.50 to prepare. The baker will make 200 pastries. Usually, about three times as many people buy small pastries than large pastries. How can the baker keep costs to a minimum while still making sure people have the pastries they want?
Surely someone out there knows how to do this!
Click here to see answer by Mathtut(3670)

Question 181392: Use synthetic substitution to find:
f(-4) for f(x)=x³+3x -5x-7
Click here to see answer by solver91311(16897)

Question 181392: Use synthetic substitution to find:
f(-4) for f(x)=x³+3x -5x-7
Click here to see answer by Edwin McCravy(8909)

Question 181768: Identify any excluded values. Then simplify the expression.
9x^3-27x^2 over 12x-36
I identified the excluded value as x=3.
I don't know what to do from here. Help!
Click here to see answer by Earlsdon(6287)

Question 181833: 2 OVER x =
2 is the numerator and x is the denomanator, I need to figure out what x is. I dont know how to slove a problem with a fraction like this. I have submited this problem before but couldnt understand the answer. So please show your work and please explain how you got the answer. And if you can could you please explain to me why the fraction is like that and what they are used for so I can better understand it in the future?
Thank You
Click here to see answer by edjones(7569)

Question 181830: 5x - 16 = 50
I submited this question before but I couldnt understand the answer I was given. Please show your work, and if you can please explain how you recieved the answer.
Thank you
Click here to see answer by edjones(7569)

Question 181877: I have tried this but I am having trouble, can you please help. Use substitution to solve each system. If it does not have one solution then put no solution or indinitely many solutions. 4X-5Y=-7 Y=5X
Click here to see answer by jim_thompson5910(28595)

Question 181876: I have tried this but I am having trouble, can you please help. Use substitution to solve each system. If it does not have one solution then put no solution or indinitely many solutions. X-5Y=36 2X+Y=-16
Click here to see answer by jim_thompson5910(28595)

Question 181875: I have tried this but I am having trouble, can you please help. Use substitution to solve each system. If it does not have one solution then put no solution or indinitely many solutions. 1/3X-Y=3 2X+Y=25
Click here to see answer by checkley77(12569)

Question 182271: 2x - y = 3 This is what i have so far but it doesn't compute
2y = 4x - 6
2x - 4x - 6 = 3
-2x - 6 = 3 divide the -2 and the 6 by -2 to get
-2x/-2 = 9/-2
x = -9/2
2y = 4(-9/2) - 6
2y = -36/2 - 6
2y = -36/2 or -18 + -6
y = -24
the answer I get is (-9/2, -24)
but when I plug them back into the equations, they don't compute. Please help
Click here to see answer by Alan3354(30993)

Question 182273: 6x - 3(y + 7) = 3
10x = y + 7
I don't know how to get this started. All I end up with are two different variables and 1 actual number. Please help
Click here to see answer by Alan3354(30993)

Question 182311: Systems of equations can be solved by graphing or by using substitution or elimination. What are the pros and cons of each method? What circumstances would cause you to use a different method?
Click here to see answer by Mathtut(3670)

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