Question

Solve the following system of equations:
a)y=-2x-1 b)2x-7y=3
x+2y=4 -5x+3y=7

Answer 1

A-
y=-2x-1 } *2 \[\rightarrow 2y =-4x -2\] -eq 1-
2y=-x+4 -eq2-

by subtracting eq1 from eq2 : \[(2y=-4x-2)-(2y=-x+4) \rightarrow 0=-3x-6 \]
so: x=-2
then from eq1 \[\rightarrow 2y=-4(-2) -2 = 8-2 =6\]
then y=6/2 =3

Answer 2

is it clear ??