Question

Find the value of the expression xy^2–y^3 for x=8.8 and y = −1.2

Answer 1

14.4

Explanation:

Put the numbers in the appropriate place in the expression and do the arithmetic.

8.8×(-1.2)² -(-1.2)³ = 1.44(8.8 +1.2) = 1.44×10 = 14.4

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Above, I factored out y^2 = 1.44 and evaluated y^2·(x -y), which is the same thing.

For "value of expression" problems, a calculator is a handy tool. The Google search box follows the order of operations faithfully, so you need to use appropriate grouping symbols when you use that calculator with rational expressions or exponents.