llaffer
Favorite Answer
I like to use long division. Don't forget to leave place holders for your x² and x terms with coefficients of zero:
. . . . . _(1/2)x²_-_(5/4)x_+_(25/8)_________
2x + 5 ) x³ + 0x² + 0x - 4
. . . . . . x³ + (5/2)x²
. . . . --------------------
. . . . . . . -(5/2)x² + 0x - 4
. . . . . . . -(5/2)x² - (25/4)x
. . . . . . ---------------------------
. . . . . . . . . . . . . (25/4)x - 4
. . . . . . . . . . . . . (25/4)x + (125/8)
. . . . . . . . . . . -------------------------------
. . . . . . . . . . . . . . . . -4 - 125/8
So first, let's simplify that remainder:
-32/8 - 125/8
-157/8
Put the remainder over the divisor:
(-157/8) / (2x + 5)
change it to multiplication of the reciprocal:
(-157/8) * 1 / (2x + 5)
and simplify:
-157 / (16x + 40)
Now add that to the quotient that we calculated:
(1/2)x² - (5/4)x + (25/8) - 157 / (16x + 40)
DWRead
Using long division:
(x³-4) ÷ (2x+5) = 0.5x² - 1.25x + 3.125 remainder -19.625
https://www.flickr.com/photos/dwread/26213521464/in/dateposted-public/