N2 a) 3^4-(-1)^4=81-1=80
b)(-3,3)^3-0,027=(-10/3)^3-27/1000=-1000/27-27/1000=-1000729/27000
v) (-7^2)×(-2/7)^2=-(7×2/7)^2=-2^4=-4
a) 2^2-(-3)^2=4-9=-5
b)(-2,5)^3×0,064=-(5/2)^3×(2/5)^3=-(5/2×2/5)^3=-1^3=-1
v)(-5^1)×(-2/5)^4=(-5)×(2/5)^4=-5×16/625=-0,128
(k+7)² = k² + 14k + 49
(k+7)² = k² + 14k + 49 - 14k - 50 = k² - 1 = (k - 1)(k + 1)
Ответ: (k - 1)(k + 1)