Start with this:
x+4)5x²+25x+16
x goes into 5x² 5x times because 
simplifies to 5x
Put 5x on top above the line:
5x
x+4)5x²+25x+16
Multiply the 5x by the x on the far left, get 5x²,
write it under the other 5x²
5x
x+4)5x²+25x+16
5x²
Multiply the 5x on top by the +4, get +20x,
write it under the +25x
5x
x+4)5x²+25x+16
5x²+20x
Draw a line at the bottom
5x
x+4)5x²+25x+16
5x²+20x
Subtract (5x²+25x)-(5x²+20x) = 5x²+25x-5x²-20x = 5x,
write it below the line under the +20x
5x
x+4)5x²+25x+16
5x²+20x
5x
Bring down the +16
5x
x+4)5x²+25x+16
5x²+20x
5x+16
The x at the far left goes into 5x, 5 times because
simplifies to +5. Put 5 on top above the line:
5x+5
x+4)5x²+25x+16
5x²+20x
5x+16
Multiply the +5 on top by the x at the far left, get 5x,
write it under the 5x at the bottom
5x+5
x+4)5x²+25x+16
5x²+20x
5x+16
5x
Multiply the +5 on top by the +4, get +20, write it under
the +16 at the bottom
5x+5
x+4)5x²+25x+16
5x²+20x
5x+16
5x+20
Draw a line at the bottom:
5x+5
x+4)5x²+25x+16
5x²+20x
5x+16
5x+20
Subtract (5x+16)-(5x+20) = 5x+16-5x-20 = -4,
write it below the line under the +20
5x+5
x+4)5x²+25x+16
5x²+20x
5x+16
5x+20
-4
The 5x+5 is the quotient and -4 is the remainder.
Edwin
