Hanna F.

asked • 11/28/16

(√7a+4 - √3-a)^2

7a+4 is under one root 
3-a is under on root
i get I need to do foil but I don't know how 
the ^2 means its squared

1 Expert Answer

By:

Michael J. answered • 11/28/16

Tutor
5 (5)

Effective High School STEM Tutor & CUNY Math Peer Leader

See tutors like this
See tutors like this
You need to square the term that is parenthesis.
 
(√7a+4 - √3-a)(√7a+4 - √3-a)
 
 
Now can you do it?
Upvote • 0 Downvote
More
Report

Hanna F.

I get all the parts in foil except the part where you have to do -√3-a * √7a+4. 
Report

11/28/16

Michael J.

You take the product of those square-roots and double the product.
 
√(7a + 4)2 - 2√(21a + 12 - 7a2 - 4a) + √(3 - a)2 
 
 
What I just did was expand the whole thing using FOIL.  Since you understood the FOIL part, you should have arrived at this.
 
The first and last terms undo the radicals and maintain the value that is under that radical.  As a result, you get
 
(7a + 4) + 2√(21a + 12 - 7a2 - 4a) + (3 - a)
 
 
Combine like terms on the first and last terms.
Report

11/28/16

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.

OR

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.