Alexey Z. answered 21d
Experienced SAT Tutor Substantially Improving Student's Test Score
If definition of x0 considered a property, then x7 * x0 = x7 * 1 = x7
Or use xm * xn = xm+n, then x7 * x0 = x7+0 = x7
Careful now! As always, the answer shall precisely match wording of the question. There is "expand", so x7 will not do as an answer!
Answer: x * x * x * x * x * x * x
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As a tutor, I always try to squeeze more out of any particular problem. In this case, I would mention the following.
- On SAT Math, where questions are multiple choice, you will find the answer in the correct form.
- On Algebra Regents, this problem can be open-ended and require reasoning. If you answered x7, you would get only partial credit (fewer points).