Question

Use synthetic division to find the result when 3x^3 + 13x^2 + x – 12 is divided by X + 4.

Answer 1

Answer:

3x² + x - 3

Step-by-step explanation:

The way I like to do it is to get rid of the x's and just use the numbers in the case of synthetic division

Pretend the square root of the division symbol

-4 √ 3 12 1 -12

Quick note: We're dividing by -4 because we're dividing by x + 4

First bring down the 3

-4 √ 3 13 1 -12

      3

Multiply it by 4 then bring add it to the next number

-4 √ 3 13 1 -12

          -12

       3   1

Add that number to the next one

-4 √ 3 13 1 -12

        -12 -4

      3    1   -3

Finally repeat the step for the last number

-4 √ 3 13 1 -12

       3 -12 -4 +12

       3    1   -3   0

Now take those bottom numbers and add back the x's but with one less power, so the starting x³ would now become x², x² would become x, and so on

3x² + 1x - 3