Question

bafi1: tìm x

\(\left(x^2+1\right)\times\left(x^3+27\right)=0\)

Answer 1

Vì x^2 >= 0 => x^2+1 > 0 

Mà (x^2+1).(x^3+27) = 0 => x^3+27 = 0 

=> x^3 = -27 = (-3)^3

=> x = -3

k mk nha

Answer 2

\(\left(x^2+1\right)\left(x^3+27\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x^2+1=0\\x^3+27=0\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x^2=-1\left(L\right)\\x^3=-27=\left(-3\right)^3\Rightarrow x=-3\end{cases}}\)

Answer 3

\(\left(x^2+1\right).\left(x^3+27\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x^2+1=0\\x^3+17=0\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x^2=-1\left(loai\right)\\x^3=-27\end{cases}}\)

\(\Leftrightarrow x^3=\left(-3\right)^3\)

\(\Leftrightarrow x=-3\)

Rất vui vì giúp đc bạn <3