Use SUBSTITUTION to solve the system
y=4x
2y-2x=12

1 Substitute
y
=
2
x
−
10
y=2x−10 into
y
=
4
x
−
8
y=4x−8.
2
x
−
10
=
4
x
−
8
2x−10=4x−8

2 Solve for
x
x in
2
x
−
10
=
4
x
−
8
2x−10=4x−8.
x
=
−
1
x=−1

3 Substitute
x
=
−
1
x=−1 into
y
=
2
x
−
10
y=2x−10.
y
=
−
12
y=−12

4 Therefore,
x
=
−
1
y
=
−
12



x=−1
y=−12