Solve the following exercise:2x2−8=x2+4 2x^2-8=x^2+4 2x2−8=x2+4
First, we move the terms to one side equal to 0.
2x2−x2−8−4=0 2x^2-x^2-8-4=0 2x2−x2−8−4=0
We simplify :
x2−12=0 x^2-12=0 x2−12=0
We use the shortcut multiplication formula to solve:
x2−(12)2=0 x^2-(\sqrt{12})^2=0 x2−(12)2=0
(x−12)(x+12)=0 (x-\sqrt{12})(x+\sqrt{12})=0 (x−12)(x+12)=0
x=±12 x=\pm\sqrt{12} x=±12
±12 ±\sqrt{12} ±12