Expand and simplify $(2a-3b)(3a-2b)$. A student combines the first and last terms in the answer to

Question

Expand and simplify $(2a-3b)(3a-2b)$. A student combines the first and last terms in the answer to part (a), writing $12a^2b^2-13ab$. Explain why this is invalid and state the correct simplified expression.

Accepted Answer

(a) $6a^2-13ab+6b^2$. (b) $a^2$ and $b^2$ are unlike terms; the answer remains $6a^2-13ab+6b^2$.

Quadratic Functions, Equations and Inequalities

Quadratic Functions, Equations and Inequalities