factor out the GCF (3) and divide everything by it, and then set it equal to zero.
since you have a degree of 2, factor it into two binomials that start with the square root of the first term and end with the square root of the second term.
3=0 is extraneous solution so we leave it, then we set each binomial equal to zero to solve for z.
note: your solutions is based on the degree or the exponent of the polynomial or the function.