For this case we have the following expression:
[tex]x^2=100[/tex]
From here we clear x, obtaining two possible results:
[tex]x = +/- \sqrt{100} [/tex]
[tex]x1=+\sqrt{100}=10[/tex]
[tex]x2=-\sqrt{100}=-10[/tex]
Therefore we must evaluate the second expression for both values of x:
For x = 10:
[tex]x^2-x=(10)^2-10
x^2-x= 100-10
x^2-x=90[/tex]
For x = -10
[tex]x^2-x=(-10)^2-(-10)
x^2-x= 100+10
x^2-x=110[/tex]
