3xsquared+7= - 8
3x^2 + 7 = - 8
3x^2 = - 8 - 7
3x^2 = - 15
x^2 = - 15/3 i = sqrt( - 1 )
x^2 = - 5
x = +/ - sqrt(- 5) , x = sqrt( - 5) = sqrt ( 5( - 1) = sqrt5*sqrt(- 1) = i*sqrt5
x = - sqrt(- 5)x = - sqrt( - 5) = - sqrt ( 5( - 1) = - sqrt5*sqrt(- 1) = - i*sqrt5