Question

Solve the system equation using substitution
y+x=2
2x-y= -4

Answer 1

Explanation:

Place : y+x=2 <==> y = 2-x

and now replace y with the x-expression:

2x-(2.x)=-4 <==> 2x-2+x= 4 <==> 3x-2 =4 <==> 3x = 6 --> x = 2

and y = 2-x so y = 2-3 = -1

so the solution is S = {(2; .1)}