Factorising quadratics (Part 2)

Maths

Quadratic expressions (9.9)

Fill in the gap: ________ is the opposite of expanding.

No, Cala is incorrect, there DOES exist a pair of factors of 8 that add to give a negative number.

Yes, Cala is correct, there DOES NOT exist a pair of factors of 8 that add to give a negative number.

Cala says that you cannot factorise x² -9x + 8 because there does not exist a pair of factors for 8 that add to give a negative number. Is she correct?

A quadratic expression  x² + bx - 20 can be factorised. Find all the possible values for b when b is negative.

A quadratic expression  x² + bx + 20 can be factorised. Find all the possible values for b when b is positive.

Factorising quadratics (Part 2)

Lesson outcome