Question

The value of expression 2a ^ 2 + 2b ^ 2 - ab for a-2, b-lis (a) 2 (b) 8 (c) 6 (d) 10

Answer 1

`2a^2 + 2b^2 - ab`
`= 8`

Explanation:

Given

`2a^2 + 2b^2 - ab`

Required

Evaluate when
`a=2\ and\ b=1`

To do this, we simply substitute 2 for a and 1 for b in
`2a^2 + 2b^2 - ab`

`2(2)^2 + 2(1)^2 - 2 * 1`

`2*4 + 2*1 - 2 * 1`

`8 + 2 - 2`

`8`

Hence:

`2a^2 + 2b^2 - ab`
`= 8`

when
`a=2\ and\ b=1`