Question 1062691
Square Root Property?  {{{3x^2+12x+1=18}}} ?
Since you posted the question twice, maybe another tutor can see the way to use "Square Root Property".


{{{3x^2+12x-17=0}}}
You could complete the square to solve, and you will eventually get to
{{{x=(-12+- sqrt(12^2-4*3*(-17)))/(2*3)}}}


{{{x=(-12+- sqrt(144+204))/(2*3)}}}


{{{x=(-12+- sqrt(348))/(2*3)}}}


{{{x=(-12+- sqrt(4*87))/(2*3)}}}


{{{x=(-12+- 2*sqrt(87))/(2*3)}}}


{{{highlight(x=-2+- sqrt(87)/3)}}}