48z^2-16z z=1/4

To find the value of the expression 48z^2 - 16z when z = 1/4, we substitute the value of z into the expression and simplify.

Step 1: Replace z with 1/4 in the expression.
48(1/4)^2 - 16(1/4)

Step 2: Simplify the expression inside the parentheses first.
48(1/16) - 16(1/4)

Step 3: Evaluate the multiplication.
3 - 4

Step 4: Subtract the values.
-1

Therefore, when z = 1/4, the value of the expression 48z^2 - 16z is -1.