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

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 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 23443: solve this pair of equations by substitution 4x+y=-19 7x-y=8 Click here to see answer by rapaljer(4670)

 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(4670)

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

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

 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(4670)

 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)