- 34
Hi !
4a⁴ - 2b² + 40 =
replace a = 2 ; b = 7
= 4ₓ2⁴ - 2ₓ7²
= 4ₓ16 - 2ₓ49
= 64 - 98
= - (98 - 64)
= - 34
Good luck !
