-8+9+5z+7x use z=3 and x=5
-8+9+5(3)+7(5)-8+9+15+351+50=51
Just substitute their values into the expression:= -8 + 9 + 5z + 7x= -8 + 9 + 5(3) + 7(5)= 1 + 15 + 35= 51In short, Your Answer would be 51Hope this helps!