Question

1)x^2-144
2)2x^2-72
3)5x^2-125
4)-x^2+81
5)x(2x-18)

Answer 1

1)

`x^2 -144=0`

`<=> x^2 =144`

\(< =>\left[{}\begin{matrix}x=12\\x=-12\end{matrix}\right.\)

2)`

`2x^2 -72=0`

`<=>2x^2 =72`

`<=>x^2=36`

\(< =>\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)

3)

`5x^2 -125=0`

`<=> 5x^2 =125`

`<=>x^2 =25`

\(< =>\left[{}\begin{matrix}x=5\\x=-5\end{matrix}\right.\)

4)

`-x^2 +81=0`

`<=> x^2 -81=0`

`<=> x^2 =81`

\(< =>\left[{}\begin{matrix}x=9\\x=-9\end{matrix}\right.\)

5)

`x(2x-18)=0`

\(< =>\left[{}\begin{matrix}x=0\\2x-18=0\end{matrix}\right.\\ < =>\left[{}\begin{matrix}x=0\\x=9\end{matrix}\right.\)

Answer 2

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