Question

${x}^{2} + 5 = 21$what are the roots x=x=

Answer 1

We have the quadratic equation:

$x^2+5=21$

We have to find the roots.

Then, we rearrange the equation as:

$\begin{gathered} x^2+5=21 \\ x^2+5-21=0 \\ x^2-16=0 \end{gathered}$

As 16 is the square of 4, we have a difference of squares that can be written as:

$\begin{gathered} x^2-16=0 \\ x^2-4^2=0 \\ (x-4)(x+4)=0 \end{gathered}$

Then, we have the function factorized and the roots are x=4 and x=-4.