Look at this from comments then you will find your answer, you’ll see why.
y
=
2
x
;
−
1
y
=
5
x
−
7
Rewrite equations:
y
=
2
x
;
−
y
=
5
x
−
7
Step: Solve
y
=
2
x
for y:
y
=
2
x
Step: Substitute
2
x
for
y
in
−
y
=
5
x
−
7
:
−
y
=
5
x
−
7
−
2
x
=
5
x
−
7
−
2
x
+
−
5
x
=
5
x
−
7
+
−
5
x
(Add -5x to both sides)
−
7
x
=
−
7
−
7
x
−
7
=
−
7
−
7
(Divide both sides by -7)
x
=
1
Step: Substitute
1
for
x
in
y
=
2
x
:
y
=
2
x
y
=
(
2
)
(
1
)
y
=
2
(Simplify both sides of the equation)
Answer:
x
=
1
and
y
