Expand and simplify
Distribute the first bracket term by term. Each term of multiplies the whole of :
Expand both products.
These four terms are the F, O, I and L of the FOIL mnemonic: , , , .
Combine the two middle terms.
The middle coefficient is the sum of the two constants, , and the last term is their product, — the shortcut worth remembering for monic quadratics.
Read off the structure of the result. has roots and , exactly the values that make each original factor vanish. Its graph is an upward parabola crossing the axis at those two points, with vertex at .
Check numerically at x = 5. The factored form gives ; the expanded form gives . At : and . Both agree.
Need to solve a different problem like this? Open the solver →