8X - 6X = -18
2X = -18
X = -9.
Hope this helps!
Find the slope first by using rise/run


We need to find the y-intercept. Substituting one of given ordered pairs. I will use (-2,-1).
Substitute x = -2 and y = -1 in the equation.

Thus the y-intercept is 4/3.
From y = mx+b, the equation is.

Answer:
Length = 12 inches, height = 3 inches
Step-by-step explanation:
First, you have to set up a proportion. 2/7, x/42.
Then, you cross multiply and get the setup of 84=7x
Finally, you divide 84 by 7 and get 12.
12 is the length, and there is no other answer that has 12 in the height. You could just do the same proportion to get 3, though.