Question

Tìm x biết :

a) 7 - \(\sqrt{x}\)= 0

b) 4\(^{x^2}\)- 1 = 0

c)2 \(^{x^2}\)+ 0.82 = 1

Answer 1

\(a)7-\sqrt{x}=0\)

\(\Rightarrow\sqrt{x}=7-0\)

\(\Rightarrow\sqrt{x}=7\)

Vậy \(x=7\)

\(b)4^{x^2}-1=0\)

\(\Rightarrow4^{x^2}=0+1\)

\(\Rightarrow4^{x^2}=1\)

\(\Rightarrow x^2=\dfrac{1}{4}\)

\(\Rightarrow x=\pm\sqrt{\dfrac{1}{4}}=\pm\dfrac{1}{2}\)

Vậy ..................

\(c)2^{x^2}+0,82=1\)

\(\Rightarrow2^{x^2}+0=1\)

\(\Rightarrow2^{x^2}=1\)

\(\Rightarrow x^2=\dfrac{1}{2}\)

\(\Rightarrow x=\pm\sqrt{\dfrac{1}{2}}\)

Vậy ......................

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