Question

Giving medal!! I need help with my math homework for radical equations. Here is the link to it, click the tab that says assessment and those are my questions.

https://bb91-k12.blackboard.com/bbcswebdav/institution/FLVS_June_2011/v11/module04/INDEX.html#47

Please help, I desperately need it

Answer 1

File won't open. :(

Answer 2

Can you type one of the problems here?

Answer 3

Actually, it appears it was just slow. I can see them now.

Answer 4

\[\sqrt{5x + 11} = 9\]

Answer 5

You want to isolate x. What operation would be the opposite of taking the square root of a number?

Answer 6

You would start by squaring both sides of the equation:\[(\sqrt{5x + 11})^{2} = 9^{2}\]


So then 5x + 11 = 81 --> 5x = 81-11 --> 5x = 70 --> x = 14

Answer 7

And the same approach would be used on the problems you have in the assessment.

Answer 8

So, for the first one: \[\sqrt{8x + 1} = 5\] -->

Answer 9

\[(\sqrt{8x + 1})^{2} = 5^{2}\] --> 8x + 1 = 25 --> 8x = 24 --> x = 3

Answer 10

So that's problem #1

For #2, you have to start by isolating the part with the square root first:

\[\sqrt{x - 7} + 5 = 11\] --> \[\sqrt{x - 7} = 6\] --> \[(\sqrt{x - 7})^{2} = 6^{2}\]-->x-7 = 36 --> x = 43

Answer 11

For #3, again begin by isolating the square root. \[-4\sqrt{x+9} = 20 --> \] \[\sqrt{x+9} = -5\] --> \[(\sqrt{x+9})^{2} = 25 --> x + 9 = 25 --> x = 16\] However, if you go back and put 16 in for x to check the answer, then you get \[-4\sqrt{16 + 9} = -4\sqrt{25} = -4(5) = -20\neq20\]

Answer 12

Got to go now, but I hope that helps to get you started!