How do you solve by substitution 3x + 2y = 23x+2y=2 and -2x + y = 82x+y=8?

1 Answer
Jun 9, 2015

The solution for the system of equations is
color(red)(x =-2 , y =4 x=2,y=4

Explanation:

3x + 2y = 23x+2y=2..........equation (1)(1)

-2x + y = 82x+y=8
y =color(red)( 8 +2xy=8+2x............equation (2)(2)

Substituting equation (2)(2) in equation (1)(1)

3x + 2y = 23x+2y=2
3x + 2color(red)((8+2x)) = 23x+2(8+2x)=2
3x + 16 +4x = 23x+16+4x=2
7x= -147x=14
color(red)(x=-2x=2

Substituting xx in equation (2)(2) to find yy

y = 8 +2xy=8+2x
y = 8 +2.(-2)y=8+2.(2)
y = 8 -4y=84
color(red)(y = 4y=4