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

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

Question 21831: a^3b^3c^3 - a^2b^3c^4+a^3b^2c^4
Click here to see answer by dkspoet(13)

Question 20929: if (a+b)/a = 6 and (b+c)/c = 9, compute the numerical value of a/c
Click here to see answer by venugopalramana(3286)

Question 23396: Factor this expression
K^2-6K+9
Click here to see answer by elima(1433)

Question 23443: solve this pair of equations by substitution
4x+y=-19 7x-y=8
Click here to see answer by rapaljer(4667)

Question 23447: This is regarding Simplification involving Addition & Subtraction:
The Problem is: -(4-5a)-(-2+3a)
My answer I get is: -6-8a (Is this correct?) It isn't working for me.
Thanks
Click here to see answer by rapaljer(4667)

Question 23451: This is regarding Simplification involving Addition & Subtraction:
Problem: (3f-f^2+fg)-(f-3f^2-2fg)
My answer is: 2f+2f^2+3fg (Is this correct?)

Click here to see answer by rapaljer(4667)

Question 23460: Assume that y varies inversely as x.If y=8 when x =2.5,find x when y=2.
Click here to see answer by Earlsdon(6294)

Question 23497: I need to solve for x in the equation nx=2nx-21n could you please help me. I have tried this way--
nx=2nx-21n
nx=n(2x-21)
where do I go from here?
Thank you

Click here to see answer by longjonsilver(2297)

Question 23503: -2X+3Y=14
X+2Y=7 HAVING PROBLEMS SOLVING THIS PLEASE HELP
Click here to see answer by elima(1433)

Question 23496: 7-2x=x-14
Click here to see answer by elima(1433)

Question 23510: If a over x plus one equals c over x, which is an expression for x in terms of c and a?
Click here to see answer by longjonsilver(2297)

Question 23511: a) Solve for x and express the answer in radical form
1 over x + 1 equals x - 4
B) Between which two consectutive integers does the positive root of this equation lie?
Click here to see answer by longjonsilver(2297)

Question 23533: Solve the System by Substitution:
y=x+4
3x+y=16
Click here to see answer by rapaljer(4667)

Question 23535: Solve the system by substitution
4x+3y=30
y=2x
Click here to see answer by rapaljer(4667)

Question 23536: x+y=1
2x-3y=?
Click here to see answer by rapaljer(4667)

Question 23499: -2x+3y=14
x+2y=7
Click here to see answer by ilana(307)

Question 23596: simplify each expression
7x - 5y - 4x + 3y
Click here to see answer by ilana(307)

Question 23592: y=3(t-s);s
Click here to see answer by ilana(307)

Question 23615: Simplify: (4x-5) + (9x+14)
Click here to see answer by MathNerdette(3)

Question 23545: Solve the system by substitution
x-7y=-22
5x+2y=1
Thanks
Click here to see answer by elima(1433)

Question 23642: I'm pretty sure this would be considered as an expression involving variables,etc. I have gotten many of these problems but still do not seem do understand or do it corretly. Please help. Here is my question:
If --- n=6 1<=n<=10

(IN OTHER WORDS: 1 is less than or equal to n, which is less than or equal to 10.)
How would you solve this?!
Click here to see answer by elima(1433)

Question 23590: ax+by=c;y
Click here to see answer by rapaljer(4667)

Question 23591: 5x-2y=-6;y
Click here to see answer by rapaljer(4667)

Question 23686: solve the system by substitution
6(x+2)-y=31
5x-2(y-3)=23
Click here to see answer by longjonsilver(2297)

Question 23685: solve the system by substitution
2(x+3)-y=7
7x-3(y-1)=9
Click here to see answer by longjonsilver(2297)

Question 23651: y=1/2x +4
2y+2x=2
Click here to see answer by elima(1433)

Question 23928: 7x+3=15x+9

Click here to see answer by Sridi(6)

Question 23940: x= -3, y= -1, z= -1 <-----------key
x^2 - 3yz + 4
Click here to see answer by longjonsilver(2297)

Question 23962: Use substitution to solve each system of equations.
X=2Y
Y=X-2
Thanks in advanced!!!
Click here to see answer by smallfry(7)

Question 23962: Use substitution to solve each system of equations.
X=2Y
Y=X-2
Thanks in advanced!!!
Click here to see answer by elima(1433)

Question 24026: If Kelly bought 3 pens and 4 pencils that cost 7.42 and Bill bought 4 pens and 5 pencils that cost 9.62 what is the cost of one pen and one pencil
Click here to see answer by rapaljer(4667)

Question 24001: Rewrite the equation so that the y is a function of x
2x=-3y+10
Click here to see answer by longjonsilver(2297)

Question 23976: (7(8-2)+9) - (13-2)(11-6)/1)
6 + 9 11 5
7 x 15 55/1
105 55
Please help, I do not understand where to start.

Click here to see answer by queenofit(120)

Question 23966: Systems of Equations
X+Y=16
2Y=-2X+2
please and thanks
Click here to see answer by rapaljer(4667)

Question 24087: 3x-y=11
x+2y=-36
Click here to see answer by rapaljer(4667)

Question 24086: 3x-y=11
x+2y=-36
Click here to see answer by rapaljer(4667)

Question 24094: A number 2 cubed?
Click here to see answer by rapaljer(4667)

Question 24093: a number decreased by 7?
Click here to see answer by rapaljer(4667)

Question 24114: 2x-3y =9
-5x-3y = 30
i know how to solve for x but not for y can u explain how to bring the x back into the equation to get y
Click here to see answer by rapaljer(4667)

Question 24117: P=4s Solve for s

Click here to see answer by rapaljer(4667)

Question 24138: 4=0.4(3D-5)
Click here to see answer by queenofit(120)

Question 24171: what is 7a-2=1 what is a?
Click here to see answer by Earlsdon(6294)

Question 24125: m=(a+b)/2 Solving for a
Click here to see answer by elima(1433)

Question 24184: I am helping a brother with his homework. How would you work this out??
(4n+5)x5=-n-24
Click here to see answer by elima(1433)

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