Question

if x+a is a factor of 2x^2+2a+5x+10 find a​

Answer 1

Answer:

a=2

Step-by-step explanation:

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

Answer 2

Answer:

• a = 12

Given:

• if x + a is a factor of 2x² 2ax + 5x + 10

To find:

• a

Solution:

Given,

f (x) = 2x² 2ax + 5x + 10

we know that,

▪︎let x + a = 0

▪︎x = - a

or

▪︎g (x) = x + a

▪︎x + a = 0

▪︎x = -a

so x is -a

substitute the values of x in this equation we get,

● f (x) = 2x² 2ax + 5x + 10

● f (-a) = 2 (-a) ² - 2a(-a) +5 (-a) + 10

● 2a² - 2a² - 5a + 10 = 0

● 5a + 10 = 0

● 5a = 10

● a = 10 / 5

● a = 2

Hence 2x² 2ax + 5x + 10 is a = 2