solve the linear system using substitution. please show me the steps!:)
x-y=-5
2x-y=-7
arrange the first equation to x = y-5
sub replace the x in the second equation with that expression
2x-y=-7
2(y-5) - y = -7
2y - 10 - y = -7
y = -7 + 10
y = 3 , now let's put that back into x = y-5
x = 3 - 5
x = -2
so x = -2, y = 3
check in the first:
is -2 - (3) = -5 ? , yes!
in the second:
is 2(-2) - (3) = -7 ? , yes!