Question

Answer 1

a)

`x^2 -196=0`

`<=>x^2 =196`

`<=>x=14` hoặc `x=-14`

b)

`x^2 =1/15`

\(< =>\left[{}\begin{matrix}x=\sqrt{\dfrac{1}{15}}\\x=-\sqrt{\dfrac{1}{15}}\end{matrix}\right.\)

c)

`-x^2 +324=0`

`<=>x^2 =324`

`<=>x=18` hoặc `x=-18`

d)

`x^2 +100=0`

`<=>x^2 =-100` (vô lí vì `x>=0AAx` )

e)

\(\sqrt{x}=\sqrt{7}\left(x\ge0\right)\\ < =>\left(\sqrt{x}\right)^2=\left(\sqrt{7}\right)^2\\ < =>x=7\)

g)

\(\sqrt{x}-3=\dfrac{1}{3}\left(x\ge0\right)\\ < =>\sqrt{x}=\dfrac{1}{3}+3\\ < =>\sqrt{x}=\dfrac{10}{3}\\ < =>\left[{}\begin{matrix}x=\sqrt{\dfrac{10}{3}}\\x=-\sqrt{\dfrac{10}{3}}\end{matrix}\right.\)