Expand the parentheses:
5z+50+10=12z+24-10z, do the arithmetic:
5z+60=2z+24, separate the variable from the constants:
5z-2z=24-60,
3z=-36,
z=-36/3=-12.
Now check the result by plugging in z=-12 into the original equation:
5(z+10)+10=5(-2)+10=-10+10=0; 12(z+2)-10z=12(-10)+120=-120+120=0.
Both sides of the equation come to zero so the solution is confirmed, z=-12.