If (x + a) is a factor of the polynomial 2x2 + 2ax + 5x + 10, find the value of a.
Since, x + a is a factor of 2x2 + 2ax + 5x + 10
∴ x + a = 0
x = -a
Put x = -a in 2x2 + 2ax + 5x + 10 = 0
2(-a)2 + 2a(-a) + 5(-a) + 10 = 0
2a2 – 2a2 – 5a + 10 = 0
-5a = - 10
a = 2