Question

What a^2-2a-48=0 by solving equations by completing the square

Answer 1

$a^2-2a-48=0 \\ (a^2-2a+1)-1-48=0 \\ (a-1)^2-49=0 \\ (a-1)^2=49 \\ \sqrt{(a-1)^2}=\sqrt{49} \\ |a-1|=7 \\ a-1=7 \ \lor \ a-1=-7 \\ a=7+1 \ \lor \ a=-7+1 \\ a=8 \ \lor \ a=-6 \\ \boxed{a=-6 \hbox{ or } a=8}$