Question

Expressed in simplified radical form, what is the value ofhttp://static.k12.com/eli/ecollege/1507/4_77809/2_60428_16_78017/0dc213a29075cc8734cff3f0a403e0d1939d84ef/media/f8bf69d21febafb52cad9671bb00682e60ee01cb/mathml_49c87b5cdfc7f05305dadef050b177f9d83dfd72_1.gif when r=2
***put the .gif in your web browser

Answer 1

plug in r=2

what do you get?

Answer 2

So, let's look at the part \[\sqrt{16r}\] first. Can you think how we might simplify this portion?

Answer 3

\(\sf\Large\sqrt{r}-\sqrt{16r}\)

\(\sf\Large\sqrt{2}-\sqrt{16\times2}=?\)

Answer 4

how would we simplify that?

Answer 5

and thank you for your help :)

Answer 6

So remember, \[\sqrt{16} = 4\] and also for any two values \[\sqrt{a*b} = \sqrt{a} * \sqrt{b}\]

So, \[\sqrt{16r} = 4 * \sqrt{r}\]

We are then left with \[\sqrt{r} - 4 * \sqrt{r}\]

We can factor the sqrt(r), to derive: \[\sqrt{r} * (1-4) = 3 * \sqrt{r} = 3 * \sqrt{2}\] (upon replacing r with 2). Do you understand all of that?

Answer 7

Sorry, my answer should be negative. So that's -3 * sqrt(2)

Answer 8

thank you guys!!! i got the answer right