Question #e1353

1 Answer
Nov 19, 2016

x=\pm\sqrt(14)

Explanation:

Equation given

x^2-2=12

Method 1

Isolate the x^2 and solve by square root.
x^2\cancel(-2)\cancel(\color(blue)(+2))=12\color(blue)(+2)
x^2=14
x=\pm\sqrt(14)

Method 2

Form a quadratic equation by making one side equal to 0, then solve by factoring said quadratic.
x^2-2\color(red)(-12)=\cancel(12)\cancel(\color(red)(-12))
x^2-14=0 lArr the factor of variable x is 0x, so...
\rArrx^2+0x-14=0 apply quadratic formula

quadratic formula below
x=(-0\pm\sqrt(0^2-4(1)(-14)))/(2(1))=(\pm\sqrt(56))/2=(\pm2\sqrt(14))/2
\rArr(\pm\cancel(2)\sqrt(14))/\cancel(2)=\pm\sqrt(14)