1. chrisGA

2. anonymous

Is this the problem $$\huge 7\sqrt{8} \times 4\sqrt{5}$$ ??

3. chrisGA

yes there both is inside ( )

4. anonymous

What one do you think is the correct answer?

5. chrisGA

A

6. anonymous

It is C

7. chrisGA

What did you multiply

8. anonymous

You multiply the 7 * 4 = 28 then you multiply $$\huge \sqrt{8} * \sqrt{5} = \sqrt{40}$$ Also quick note, this symbol * means to times Now we have $$\huge 28 * \sqrt{40}$$ but we need to break down the $$\huge \sqrt{40}$$ and we can do that by finding a perfect square and a non perfect square and then timing them together. A perfect square would be $$\huge \sqrt{4} = 2$$ and a non perfect square would be $$\huge \sqrt{10}$$ Now notice that $$\huge 28 * \sqrt{4} * \sqrt{10} = \sqrt{40}$$ so we are still using $$\huge \sqrt{40}$$ but we have just changed its form. So now we have $$\huge 28 * \sqrt{4} * \sqrt{10} = 2\sqrt{10}$$ Now we take $$\huge 2\sqrt{10}$$ and times it by 28 so we have $$\huge 28 * 2\sqrt{10} = 56\sqrt{10}$$

9. chrisGA

oh ok