Question

Fully Factor 3x^2 – 16x + 20

A. (3x + 10) (x - 2)
B. None of the answers are correct
C. (3x – 10) (x - 2)
D. (3x² - 4) (x - 5)

Answer 1

C. (3x2 - 10) (x - 2)

Explanation:

3x^2 - 16x +20

Step 1: Sum = - 16x

Product = 60x^2

Step 2: Find 2 numbers that their sum is -16 and their product is 60. If you do that correctly, then you will get two numbers: 10 and -6

Step 3: Replace -16x with the two numbers found in step 2, then you will have; 3x^2 - 6x - 10x + 20

Step 4: Factorise the equation in step 3, like so;

(3x^2 - 6x)(- 10x + 20)

3x(x - 2) -10(x - 2)

(3x - 10)(x - 2)

To check if the answer is correct, expand the bracket: (3x - 10)(x - 2)

If the bracket is opened properly, you will get 3x^2 - 16x + 20