Consider the following system of linear equations:

\(5x-2y=-7\)...(1)

\(x=-2y+1\)...(2)

Substitute equation (1) in equation (2):

\(5(-2y+1)-2y=-7\)

\(-10y+5-2y=-7\)

\(-12y=-7-5\)

\(-12y=-12\)

\(y=1\)

\(\displaystyle{x}=-{2}\times{1}+{1}\)

\(=-2+1\)

\(=-1\)