We have to isolate x on each case,
First equation
[tex]\begin{gathered} \sqrt[]{x^2+7}=4 \\ \sqrt[]{x^2+7}^2=4^2\text{ raising both sides to the power of 2} \\ x^2+7=16 \\ x^2=16-7\text{ Isolating x\textasciicircum{}2 , we have} \\ x^2=9\text{ } \\ \text{the root of 9 is 3 or -3 , the answer is -3 because of the options} \end{gathered}[/tex]
Second equation
[tex]\begin{gathered} \sqrt[3]{1-x}=-1 \\ \sqrt[3]{1-x}^3=-1^3\text{ Raising both sides to the power of 3} \\ 1-x=-1\text{ } \\ 1+1=x\text{ Isolating x} \\ x=2 \\ \text{Answer is x=2} \end{gathered}[/tex]
Third equation
[tex]\begin{gathered} \sqrt[4]{x-2}=2 \\ \sqrt[4]{x-2}^4=2^4\text{ Raising both sides to the power of 4} \\ x-2=16 \\ x=16+2=18 \\ \text{Answer is x=18} \end{gathered}[/tex]
