Question

Recall that the product (a + b)(a - b) is the

Answer 1

Answer:

The third option (9+$3\sqrt{7}$-$3\sqrt{7}$-$\sqrt{49}$)

Step-by-step explanation:

With FOIL, this can be expanded. (a+b)(a-b) is equal to a²+ab-ab-b² or a²-b².

In this case, all the answers have 4 terms, so we want the first option. This makes the equation 3²+(3×$\sqrt{7}$)-(3×$\sqrt{7}$)-($\sqrt{7}$)².

Solving these gives 9+$3\sqrt{7}$-$3\sqrt{7}$-7. This is the same as  9+$3\sqrt{7}$-$3\sqrt{7}$-$\sqrt{49}$.

**This content involves multiplying with surds and expanding perfect squares, which you may wish to revise. I'm always happy to help!

Answer 2

Answer:

D

Step-by-step explanation:

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