Question

Tìm x (giải chi tiết)

a) x(x-1)=0

b) (x+2)(x-4)=0

c) x³. x² = 2⁸ : 2³

d) 3^x-3 - 3² = 2.3²

Answer 1

a) \(x\left(x-1\right)=0\)

\(\Rightarrow x=0\) hoặc \(x-1=0\)

+) \(x=0\)

+) \(x-1=0\Rightarrow x=1\)

Vậy \(x\in\left\{0;1\right\}\)

b) \(\left(x+2\right)\left(x-4\right)=0\)

\(\Rightarrow x+2=0\) hoặc \(x-4=0\)

+) \(x+2=0\Rightarrow x=-2\)

+) \(x-4=0\Rightarrow x=4\)

Vậy \(x\in\left\{-2;4\right\}\)

c) \(x^3.x^2=2^8:2^3\)

\(\Rightarrow x^5=2^5\)

\(\Rightarrow x=2\)

Vậy \(x=2\)

d) \(3^{x-3}-3^2=2.3^2\)

\(\Rightarrow3^{x-3}=18+9\)

\(\Rightarrow3^{x-3}=27\)

\(\Rightarrow3^{x-3}=3^3\)

\(\Rightarrow x-3=3\)

\(\Rightarrow x=6\)

Vậy \(x=6\)

Answer 2

a) x(x-1)=0

=> x.x =0+1

=> x.x =1

=> x^2 =1

=> x^2 =1^2

=> x =1