Question

Tìm x

( x - 3 )³ + 2². 5 = -7

Answer 1

\((x-3)^3+2^2\cdot5=-7\\\Rightarrow (x-3)^3+4\cdot5=-7\\\Rightarrow(x-3)^3+20=-7\\\Rightarrow(x-3)^3=-7-20\\\Rightarrow(x-3)^3=-27\\\Rightarrow(x-3)^3=(-3)^3\\\Rightarrow x-3=-3\\\Rightarrow x=-3+3=0\)

Answer 2

\(\left(x-3\right)^3=-7-20=-27\Leftrightarrow\left(x-3\right)^3=\left(-3\right)^3\)

\(\Leftrightarrow x-3=-3\Leftrightarrow x=0\)