Question

CEREAL The volume of a box of cereal in square inches can be represented by

the expression 2x² + 30x + 108. Factor the expression.

Answer 1

2(x+6)(x+9)

Explanation:

Factor out a 2.

The result is 2(x^2+15x+54).

From here, many ways are possible, but for simplicity, we’ll go for a guess and check method. Assuming you know how it works, 2 numbers (we’ll call them a and b) satisfy a+b=15 and ab=54. After a bit of guessing, we can derive that the 2 numbers are 6 and 9. Our factored expression resembles 2(x+a)(x+b), so our factored expression is

2(x+6)(x+9)