Question

If 4x^2 - 100 = 0, the roots of the equation are

Answer 1

$4x^2-100=0 \ \ \ \ \ \ |+100 \\ 4x^2=100 \ \ \ \ \ \ \ \ \ \ \ |\div 4 \\ x^2=25 \\ x=\pm \sqrt{25} \\ x=\pm 5 \\ x=-5 \hbox{ or } x=5$

The answer is (3) -5 and 5.