gradient is
if you have
ax+by=c
gradient (aka slope)=a/b
we have
-4x+2y=16
a=-4
b=2
gradient=-4/2=-2
y intercept is when the line crosses the y axis, also that is when x=0 so set x=0 and solve for y
-4(0)+2y=16
0+2y=16
2y=16
divide 2
x=8
y intercept=8
gradient=-2
y intercept=8 (y=8 aka point (0,8))