Question

Y = -4x - 24
y + 2x = 8
How would I solve by substitution step by step?

Answer 1

x=-16

y=40

Explanation:

y=-4x-24

y+2x=8

its the same y. Use substitution

(-4x-24)+2x=8

-2x-24=8

-2x=32

x=-16

We found x!

substitute x in either equation

y+2x=8

y+2(-16)=8

y-32=8

y=40

Answer 2

Answer: (-16, 40)

Step-by-step explanation: Using substitution, you can but the first y=-4x-24 into the second equation y+2x=8. So, you take what y is (which is -4x-24) and substitute it for the second y in the equation y+2x=8.

Your equation should now look like this (-4x-24) + 2x = 8.

You can then solve -4x -24 +2x =8. Combine like-terms (-4x+2x) to get -2x-24=8. Then use inverse operations and add 24 from both sides (so from the -2x-24 side and 8 side). This will then give you -2x=32. divide both sides from -2x to get:

x = -16

Then, plug in x= -16 into the first equation (y= -4 (-16) - 24). Then use PEMDAS and multiply -4 and -16 to get +64. Subtract 24 to get:

y = 40