Question #e1353

1 Answer
seol
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)#

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