SOLUTION: Solve by the substitution method. 4x+7y = 35 -3x+y = 30 Can someone please help me with this.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve by the substitution method. 4x+7y = 35 -3x+y = 30 Can someone please help me with this.      Log On


   

Question 137500: Solve by the substitution method.
4x+7y = 35
-3x+y = 30
Can someone please help me with this.
Answer by oscargut(2103) About Me  (Show Source):
You can put this solution on YOUR website!
4x+7y = 35
-3x+y = 30
y=3x+30 (from 2nd eq)
then
using it at 1st eq we have
4x+7(3x+30)=35
25x+210=35
25x=-175
x=-7
y=3(-7)+30=9
Answer: x=-7,y=9