Question

Giúp mk đi rồi mk kb 

1) ( x mũ hai +1 ) = -4

2) (x-5).(3-x)=0

Answer 1

\(\left(x^2+1\right)=-4\)

\(x^2+1+4=0\)

\(x^2+5=0\)

\(x^2=-5\)

\(\Rightarrow x\in\varnothing\)

vậy \(x\in\varnothing\)

2) \(\left(x-5\right)\left(3-x\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-5=0\\3-x=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=5\\x=3\end{cases}}\)

vậy \(\orbr{\begin{cases}x=5\\x=3\end{cases}}\)

Answer 2

2) \(\left(x-5\right)\left(3-x\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-5=0\\3-x=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=5\\x=3\end{cases}}\)

1) \(x^2+1=-4\)

\(x^2=-5\)

\(\Rightarrow x\in\varnothing\)