Question

(a-4)в квадрате-2a(5a-4) при значение а=-1/3

Answer 1

(a-4)^2-2a(5a-4) = a^2-8a+16-10a^2+8a = -9a^2+16; при a = -1/3 -9a^2+16 = -9(-1/3)^2+16 = -9*1/9+16 = -1+16 = 15  

Answer 2

a^2-8a+16-10a^2+8a=0

-9a^2+16=0   *(-1)

(3a-4)(3a+4)=0

a=-1/3

ответ    -15