Question

9х2-7(х+4)(4-х)-(1-4х)2=15

Answer 1

9x^2-7(x+4)*(4-x)-(1-4x)^2=15
16x^2-112-1+8x-16x^2-15=0
16x^2-113+8x-16x^2-15=0
-113+8x-15=0
-128+8x=0
x=128/8
x=16

Answer 2

Спс