How do you solve sqrt(3x^2-11)=x+1 and identify any restrictions?

1 Answer
Mar 29, 2018

x=3

Explanation:

color(blue)"square both sides"

rArr(sqrt(3x^2-11))^2=(x+1)^2

rArr3x^2-11=x^2+2x+1

rArr2x^2-2x-12=0larrcolor(blue)"in standard form"

rArr2(x^2-x-6)=0

rArr2(x-3)(x+2)=0

"equate each factor to zero and solve for x"

x-3=0rArrx=3

x+2=0rArrx=-2

color(blue)"As a check"

Substitute these values into the equation and if both sides are equal then they are the solutions.

sqrt(27-11)=sqrt16=4" and "3+1=4

sqrt(12-11)=1" and "-2+1=-1

"the solution is "x=3

x=-2" is an extraneous solution"