Question

Solve, using the substitution method.

2x + 4y = 16
x – 7 = – 4y

Answer 1

1. x+2y=6 or x=6-2y
3x-2y=2
3(6-2y)-2y=2
18-6y-2y=2
18-8y=2
-8y=-18+2
-8y=-16
y=-16/-8
y=2 ans.
x+2*2=6
x+4=6
x=6-4=2 ans.
Proof:
3*2-2*2=2
6-4=2
2=2
I leave the rest for you to practice with.

3. 4x+y=7
2x+5y=-1


5. 3x+2y=-2
6x-y=6
Solve the system using the elimination method. Show all your steps.
7. -3x+3y=3
3x+y=9 add.
---------------------------------
4y=12
y=12/4
y=3 ans.
3x+3=9
3x=9-3
3x=6
x=6/3
x=2 ans.
Proof:
-3*2+3*3=3
-6+9=3
3=3
I'll leave the rest for practice.
9. -5x+12y=20
x-2y=-6
11. 3x+2y=1
4x+ 6y= 7

Answer 2

A. (0, -7)

B. (0, 7/4)

C. (9, -1/2)

D. (17, -5/2)

Answer 3

Sub in the second into the first, so:
x – 7 = – 4y
becomes:
x=7-4y
Now plug it into the first equation:
\[\LARGE 2(7-4y) + 4y = 16\]
\[\LARGE 14-8y+4y=16\]
Combine like terms:
\[\LARGE -4y=2\]
Now divide:
\[\LARGE y=-\frac{1}{2} \]
So now we have the y-value:
\[\LARGE (x, -\frac{1}{2})\]

Can you find x?

Answer 4

yes, thank you

Answer 5

You're welcome!