Question

a) x (x+3)=0

b)(x-2)(5-x)=0

c)(x-1)(x²+1)=0

Answer 1

a, x(x+3)=0

=>x hoặc x+3=0

=>x+3=0

=>x=0-3

=>x=-3

=>x= 0 hoặc x=-3

b, (x-2)(5-x)=0

=>x-2 hoặc 5-x=0

=>x= 0+2 hoặc x= 5-0

=>x= 2 hoặc x= 5

c, (x-1)(x²+1)=0

=>x-1 hoặc x²-1=0

=>x=1   ->(1)

x²-1=0

=>x²=1

=>x=1

Vậy x=1

Answer 2

a) x(x+3)=0

=>x=0 hoặc x+3=0

                    x=-3

Vậy x=0; x=-3

b)(x-2)(5-x)=0

=>x-2=0 hoặc 5-x=0

    x=2              x=5

Vậy x=2; x=5

c)(x-1)(x²+1)=0

=>x-1=0 hoặc x²+1=0

    x=1              x²=-1(vô lí)

Vậy x=1

Answer 3

a)\(x\left(x+3\right)=0\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x+3=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x=-3\end{array}\right.\)

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

\(\Leftrightarrow\left[\begin{array}{nghiempt}x-2=0\\5-x=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=2\\x=5\end{array}\right.\)

c)\(\left(x-1\right)\left(x^2+1\right)=0\)

\(\Leftrightarrow x-1=0\) (vì \(x^2+1>0\))

\(\Leftrightarrow x=1\)

Answer 4

giúp vs mk đag cần gấp

 

Answer 5

a) \(x\left(x+3\right)=0\)

\(\Leftrightarrow\begin{cases}x=0\\x+3=0\end{cases}\)

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

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

\(\Leftrightarrow\begin{cases}x-2=0\\5-x=0\end{cases}\)

\(\Rightarrow\begin{cases}x=2\\x=5\end{cases}\)

c) \(\left(x-1\right)\left(x^2+1\right)=0\)

\(\Leftrightarrow x-1=0\)

\(\Rightarrow x=1\)