Question

If (x+a) is a factor of 2x² + 2a + 5x + 10, then find a.



I need full explanation. ​

Answer 1

Step-by-step explanation:

ANSWER

Given f(x)=2x

2

+2ax+5x+10

g(x)=x+a

x+a=0

x=−a

f(−a)=2(−a)

2

+2a(−a)+5(−a)+10

⇒+2a

2

−2a

2

−5a+10=0

⇒5a=10

⇒a=

5

10

∴a=2