Question

solve each system by substitution.
-8x-4y=-4
y=x-8

Answer 1

-8x - 4y = - 4

Now you want to plug in y, we know y = x - 8

-8x - 4(x - 8) = -4

Now solve for x

-8x - 4x +32 = -4

Now add like terms

-12x + 32 = -4

Subtract 32

-12x = -36

Divide by -12 \[x = \frac{ -12 }{ -36 }\]

x = 3

Now take that 3 and plug it into your equation for x

-8(3) - 4y = -4
Now you just need to solve for y

Your x coordinate is (3, ?) You'll get your y coordinate by solving for y

Answer 2

Multiply the second equation by 4 so that your coefficients of y are (-) of each other:
4y=4x-32
Then add the two equations. Since your y coeeficients were opposite (-) they will cancel out and go to 0, leaving you with one variable:
-8x=-4+4x-32
Subtract 4x, and combine your basic numbers
-12x=-36
Divide by -12
x=3
Now plug this into either equation (second is simpler) to get y:
y=3-8=-5
So the solution is (3,-5)

Answer 3

can you show me how to plug this into the equation