Evaluate each expression for the given values of the variables.

7. 8z+3; z=8 8.3 (7+x square); x=2

9. s-5t+s square; s=4, t=-1 10. x-y 3 square; x = - 7, y=3

All of these involve simple substitution. Just replace the variable with the actual value.

8z + 3 >>> 8 (8) + 3 = 64 + 3 = 67

3 (7 + x^2) >>> 3 (7 + 2^2) = 3 (7 + 4) = 3 (11) = 33

s - 5t + s^2 >>> 4 - 5 (-1) + 4^2 = 4 + 5 + 16

Get the trend? I am not sure I get that last one, is it:

x - y*3^2?