Question

Metodo de suma resta y igualacion

x-y=4

2x-2y=8

Answer 1

A) x-y=4
y= 4-x
-y=8-2x
y=-8+2x

4-x=8+2x
x-2x=-4-8
-3x= -12

x=    -12/-3

x= 9



9-y=4
y=4-9
y= -5 


(9)-(-5)=4
9-5=4
4=4


b)2x-2y=8

2(9)-2(-5)=8
18-10=8
8=8