In y = mx + b form, the slope will be in the m position and the y int will be in the b position
y = mx + b
slope(m) = 8
y int (b) = 12
sub
y = 8x + 12
now, to find the x int, sub in 0 for y and solve for x
0 = 8x + 12
-8x = 12
x = -12/8 which reduces to - 3/2....so ur x int is -3/2 or (-3/2,0)