Question

Как решить (2х-15)(2х+15)-4х+х-14,при х=60

Answer 1

$4 {x}^{2} - 225 - 4x + x - 14 = 4 {x}^{2} - 3x - 239 = 4 \times {60}^{2} - 3 \times 60 - 239 = 4 \times 3600 - 180 - 239 = 13981$

Answer 2

(2×60-15)×(2×60+15)-4×60+60-14=13981