Answer:
Look at the equations:
y
=
−
9
x
−
21
and
y
=
5
x
+
7
Because both equations equal (y), they both equal the same.
If an equations says "
y
=
−
9
x
−
21
" , that means we can replace (y) with
−
9
x
−
21
.
Therefore when i take the equation:
y
=
5
x
+
7
, we can replace (y) to get:
−
9
x
−
21
=
5
x
+
7
Now isolate (x):
−
9
x
−
21
=
5
x
+
7
⇔
−
21
=
14
x
+
7
⇔
−
28
=
14
x
⇔
x
=
−
2
Step-by-step explanation:
hope it helps you!!!!!!!!
<u>Let's solve this problem step-by-step</u>
<u>Let's set</u>:
2x + 6y = 36 -- equation 1
x + 4y = 20 -- equation 2
(equation 2) * 2
2x + 8y = 40 -- equation 3
(equation 3) - (equation 1)
2y = 4
y = 2 -- equation 4
Plug (equation 4)'s value of y into (equation 2)
x + 4(2) = 20
x = 20 - 8
x = 12
<u>Thus x = 12 and y = 2</u>
<u>Let's check, by substituting these values</u>

<u>Answer: x = 12 and y = 2</u>
Hope that helps!
Graph 1: Domain = 2 <= x < 12
Graph 1: Range = {2,4}
Graph 2: Domain = 3 <= x <= 10
Graph 2: Range = -6 <= y <= 4
Graph 3: Domain = 4 < x < 11
Graph 4: Range = -6 <= y < 2