I do not understand radical equations.

12 times the square root of z-1=3 times the square root 3z+1050.

If 12 times the square root of z-1=3 times the square root 3z+1050

mean :

12 * sqrt ( z - 1 ) = 3 * sqrt ( 3 z + 1050 )

then :

12 * sqrt ( z - 1 ) = 3 * sqrt ( 3 z + 1050 ) squared both sides

12 ^ 2 * ( z - 1 ) = 3 ^ 2 * ( 3 z + 1050 )

144 * ( z - 1 ) = 9 * ( 3 z + 1050 )

144 z - 144 = 9 * 3 z + 9 * 1050

144 z - 144 = 27 z + 9450

144 z - 27 z = 9450 + 144

117 z = 9594 Divide both sides by 117

z = 9594 / 117

z = 82