Final answer:
The value of the expression 8s - t² for s=9 and t=11 is -49. This is found by substituting the given values into the expression, resulting in 72 - 121.
Step-by-step explanation:
To evaluate the expression 8s - t² for s = 9 and t = 11, first substitute the given values for s and t into the expression. Thus, the expression becomes 8(9) - 11². Next, calculate the square of t, which is 11² = 121, and the product of 8 and s, which is 8 × 9 = 72.
Finally, subtract the square of t from the product of 8 and s, resulting in 72 - 121, which equals -49. Therefore, the value of the expression 8s - t² when s = 9 and t = 11 is -49.