The original formula is
[tex](X^2-Z)(2Z+5)[/tex]and we are asked to replace X by 5, Y by -3 and Z by 7:
-let's replace first X for 5 in the original formula:
[tex](5^2-Z)(2Z+5)=(25-Z)(2Z+5)[/tex]Now we are going to replace Z by 7 in the last formula:
[tex](25-7)(2(7)+5)=(18)(14+5)=(18)(19)=342[/tex]so the final result is 342
