please help me with this

[tex]3z^{2} -10z-5[/tex]
Insert the value of z into the equation
[tex]3(4)^{2} -10(4)-5[/tex]
[tex]3(16) -40-5[/tex]
[tex]48-40-5[/tex]
[tex]3[/tex]
The value of the expression [tex]3z^{2} -10z-5[/tex] when [tex]z=4[/tex] is 3