If (x + a) is a factor of 2x^{2} + 2ax + 5x + 10, find a.

Given,

2x^{2} + 2ax + 5x + 10

Factor = (x + a)

Now by using factor theoram we get,

f( – a) = 2a^{2} – 2a^{2} – 5a + 10 = 0

– 5a + 10 = 0

a = 2

Therefore the value of a = 2.