What do you want to calculate?
CALCULATE IT!
Solve
Graph
Lesson
Problem:
Solve
x
+
2
y
=
−
6
;
3
x
+
8
y
=
−
20
Steps:
I will solve your system by substitution.
(You can also solve this system by elimination.)
x
+
2
y
=
−
6
;
3
x
+
8
y
=
−
20
Step: Solve
x
+
2
y
=
−
6
for x:
x
+
2
y
+
−
2
y
=
−
6
+
−
2
y
(Add -2y to both sides)
x
=
−
2
y
−
6
Step: Substitute
−
2
y
−
6
for
x
in
3
x
+
8
y
=
−
20
:
3
x
+
8
y
=
−
20
3
(
−
2
y
−
6
)
+
8
y
=
−
20
2
y
−
18
=
−
20
(Simplify both sides of the equation)
2
y
−
18
+
18
=
−
20
+
18
(Add 18 to both sides)
2
y
=
−
2
2
y
2
=
−
2
2
(Divide both sides by 2)
y
=
−
1
Step: Substitute
−
1
for
y
in
x
=
−
2
y
−
6
:
x
=
−
2
y
−
6
x
=
(
−
2
)
(
−
1
)
−
6
x
=
−
4
(Simplify both sides of the equation)
Answer:
x
=
−
4
and
y
=
−
1
