Question

what should be added to the polynomial x^3-5x+3 so that 3 is a zero of the polynomial

Answer 1

$x {}^{3} - 5x + 3 \\ put \: x = 3 \\ 3 \times 3 \times 3 - 5 \times 3 + 3 \\ = 27 - 15 + 3 \\ = 15 \\ here \: we \: see \: that \: if \\ \: we \: add \: ( - 15) \\ then \: polynomial \: will \: \\ be \: zero \: \\ so \: answer = \: - 15$