In the expansion of (x + 3)(x - 5), what is the coefficient of x?

Correct answer to question 14 (Mathematics Knowledge): -2

Method

Multiplying out gives x squared - 5x + 3x - 15, and the two middle terms combine to -2x. When both brackets start with plain x, the middle coefficient is simply the sum of the two constants: 3 + (-5) = -2.