Precalculus
9 Online
OpenStudy (anonymous):
sqrt of 3x + 4 minus sqrt of 2x - 7 equals 3
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
\[\sqrt{3x+4} - \sqrt{2x-7} = 3\]
OpenStudy (anonymous):
Could you help me with this problem? :)
OpenStudy (anonymous):
Yes. Any ideas how to start? I am a teacher and I will try to drag it out of you rather than just tell you. I won't have you suffer too much though.
OpenStudy (anonymous):
use the difference of two squares
OpenStudy (anonymous):
I figured you could square both sides first?
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
Separate the roots first by adding the subtracted one to both sides then let the squaring begin.
OpenStudy (anonymous):
so add 2 x + 7
OpenStudy (anonymous):
\[\sqrt{3x+4} = 3 + \sqrt{2x-7}\]
OpenStudy (anonymous):
So how would I go about getting rid of the 3
OpenStudy (anonymous):
You have to square both sides. The right is a binomial being squared. Careful.
(3 + sqrt)(3 + sqrt)
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
So it would be 3x + 4 = ( 3 + sqrt of 2x - 7 ) ( 3 + sqrt of 2x - 7)?
OpenStudy (anonymous):
Yes
OpenStudy (anonymous):
Okay so then the next step would be toooo...
OpenStudy (anonymous):
FOIL the right side.
Then, believe it or not gather like terms so sqrt is alone and square both sides again.
OpenStudy (anonymous):
Okay I offically suck at foiling
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
3*3 + 3 * sqrt + 3 * sqrt + sqrt ^ 2
OpenStudy (anonymous):
So would it be 9 + 3 sqrt of 2x - 7 + sqrt of 2x-7 squared
OpenStudy (anonymous):
\[3x +4 =9 + 6\sqrt{2x-7}+2x+7\]
Simplify and isolate the sqrt
OpenStudy (anonymous):
So would I add the 3x + 4 and the 2x + 7
OpenStudy (anonymous):
Gather terms on the right.
Move anything not sqrt to the left.
What do you get?
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
sqrt of 2x - 7 + 5 x + 11 = 22 ? that's probably wrong
OpenStudy (anonymous):
3x + 4 = 2x + 16 + sqrt
OpenStudy (anonymous):
Okay would I square both sides now?
OpenStudy (anonymous):
You there
OpenStudy (anonymous):
Here
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
Gather all but 6 sqrt on left side.
OpenStudy (anonymous):
So would I add the 3x+4 and 2x+16
OpenStudy (anonymous):
(3x+4) - (2x+16) to gather everything to the left
OpenStudy (anonymous):
So then it would be 3x + 4 - 2 x + 16 = sqrt of 2x-7 ?
OpenStudy (anonymous):
-16 and 6sqrt
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
What? I'm more visual learner..
OpenStudy (anonymous):
Where did you get a 6 from???
OpenStudy (anonymous):
Way up where we did foil you see 6 * sqrt.
OpenStudy (anonymous):
So how did you get -16 and 6 sqrt
OpenStudy (anonymous):
Big picture coming. Hang on.
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
Alrighty
OpenStudy (anonymous):
Any luck??
OpenStudy (anonymous):
I am getting there, it's just getting the visual you need takes some time.
OpenStudy (anonymous):
I had a sign error. How disgusting!
OpenStudy (anonymous):
Oh okay
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (anonymous):
|dw:1370243300348:dw|