Question

If 8a^2+ 2b^2= 10 and ab = 2, then what is the value of (2a+b)^2

Answer 1

13

Explanation:

We have:

8a^2 + 2b^2 = 10

Dividing both sides by 2,

=> 4a^2 + b^2 = 5

or (2a)^2 + b^2 = 5

We also have ab = 2

=> (2a + b)^2

= (2a)^2 + 2(2a)(b) + b^2

= (2a)^2 + b^2 + 4ab

= 5 + 4(2)

= 5 + 8

= 13