
Andrew P. answered 05/18/21
Perfect score on SAT math (800)
The best strategy for polynomial division is to try to match your divisor to the highest power x in the dividend until it is no longer possible. In this case, the highest power in the dividend is x3. To match x3, multiply the divisor by x2.
(x+4) * x2 = x3+4x2
Now, write x2 off to the side and subtract the term above (x3+4x2) from your dividend.
(x3+6x2+11x+7) - (x3+4x2) = 2x2+11x+7
Next, we repeat the process; match the divisor to the new dividend. In this case, we are trying to match x to 2x2, so we should multiply the divisor by 2x
(x+4) * 2x = 2x2+8x
And subtract:
(2x2+11x+7) - (2x2+8x) = 3x + 7
Repeat the process once more, but don't forget what we multiplied the divisor by earlier. So far we have x2 and 2x.
To match x+4 to 3x+7, we should multiply by 3.
(x+4) * 3 = 3x + 12
(3x + 7) - (3x+12) = -5
At this point, we can go no further. There is no way to subtract x + 4 from -5. Thus, -5 is our remainder. Our quotient is determined by the sum of all the terms we multiplied the divisor by to match the dividend. In total, our quotient is x2+2x+3.
Thus,
Quotient: x2+2x+3
Remainder: -5