Exercise 1 Page 74

We want to write the product of z and x-y as a mathematical expression. To do this, we should think about what each phrase is telling us. The product of means that we are multiplying. The factors being multiplied are z and x-y. In this exercise, x-y is considered a single factor of the product, so we need to write it in parentheses. & The product of z and (x-y) & z * (x-y) When we have a multiplication involving parentheses, we do not need to include any kind of multiplication symbol. Knowing that, let's simplify the obtained expression a bit more. z * (x-y) ⇔ z(x-y) This corresponds to option A.