Question

Упростите выражение 2х(х-8)+5х(2х+6)-24 при х=-4

Answer 1

$2 {x}^{2} - 16x + 10 {x}^{2} + 30x - 24 = 12 {x}^{2} + 14x - 24 = 12 \times ( { - 4}^{2} ) - 14 \times 4 - 24 = 12 \times 16 - 56 - 24 = 192 - 80 = 112$