Question

If (x+a)is a factor of 2x2+2ax+5x+10;findthe value of a

Answer 1

$let \: f(x) = 2 {x}^{2} + 2ax + 5x + 10 \\ x + a \: \: is \: \: a \: \: factor. \: so \: \: f( - a) = 0 \\ 2 \times {( - a)}^{2} + 2a \times - a + 5 \times - a + 10 = 0 \\ 2 {a}^{2} - 2 {a}^{2} - 5a + 10 = 0 \\ a = 2$