Ответ:

Объяснение:

1) ((t^8)^4*t^-31)/t^2=t^((8*4-31)-2)=t^-1

2) 16-3(x+2)=2+4x

16-3x+6=2+4x

-7x=-20

x=2*6/7

(-5x-6)(3+4x)=-15x-20x^2-18-24x=20x^2-39x-18

(3x+1)^2=6x^2+6x+1

(a-5)(4a-5)-(5-2a)^2=4a^2-5a-20a+25-25+20a-4a^2=-5a