Expert: Abe Mantell - 12/25/2009

Question
Hello, I am a college student and I need help, pronto, with an equation, please and thank you.

2x-4y=34
  7y=-34-5x

Mattie

Answer
Hello,

I gather you want to solve the system of equations, for x & y...yes?

Two popular ways:
1. By Elimination - multiply one or both equations by non-zero numbers so
.  when added, one of the variables gets eliminated and we can then solve
.  for the remaining variable.
2. By Substitution - solve one of the equations for one variable, then
.  substitute that expression into the other equation to solve for the
.  remaining variable.

I'll do by substitution.  Taking the first equation, solve for x:
2x=34+4y, now divide by 2 ==> x=17+2y, now substitute that into
the other equation: 7y=-34-5(17+2y), now solve for y.
==> 7y=-34-85-10y, adding 10y to both sides: 17y=-119, dividing by 17
gives: y=-7, now x=17+2(-7), so x=3

x=3, y=-7

Abe