To find the y intercept of y = x^4 – 3x^5 – 8 + x^2, substitute x=0 and
solve for y

y = 0^4 – 3(0)^5 – 8 + (0)^2 
y = 0 - 0 - 8 + 0 =
y = -8

So the y intercept of that graph is (x,y) = (0,-8)

To find the y intercept of y = 2x – 18, substitute y=0 and
solve for x

  y = 2x – 18
  0 = 2x - 18
-2x = -18
  x = 9

So the x intercept of that graph is (x,y) = (9,0)

So now the problem becomes:

Find the equation of the line which passes through the
two points (0,-8) and (9,0)

The slope is given by the formula:

m = 

m = 

m = 


So the y intercept of that graph is (x,y) = (0,-8),

so b = -8.

We can just use y = mx + b and get

y = x - 8

Edwin