By substituting the values into 8x-4y = 18

x = 2.25 when y = 0

x = 0 when y = -4.5

x = 1 when y = -2.5

x = 3.75 when y = 3

:--

8x - 4y = 18

( 9/4 , 0 ) , ( 0 , - 9/2 ) , ( 1 , -5/2 ) , ( 15/4 , 3 )

I'll do the first one. You can do the others from there following the same steps:

8x - 4y = 18

You are told that y = 0 and need to solve for x. So substitute the value and solve for the unknown:

8x - 4(0) = 18

8x - 0 = 18

8x = 18

x = 18/8

x = 9/4

Now do the same with the other three.