SOLUTION: Please help! (2 x the square root of 3x - the square root of 5)(2 x the square root of 3x + the square root of 5)=

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Question 22954: Please help! (2 x the square root of 3x - the square root of 5)(2 x the square root of 3x + the square root of 5)=
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
%282x+%2Asqrt%283x%29+-+sqrt%285%29+%29%2A%282x%2A+sqrt%283x%29+%2B+sqrt%285%29%29

This is a simple F OI L problem. I say simple because it will be a LOT easier than it looks!!

First: 2x+%2Asqrt%283x%29%2A2x+%2Asqrt%283x%29+=+4x%5E2%2A+3x

Outer: 2x+%2Asqrt%283x%29+%2A+sqrt%285%29+=+2x%2A+sqrt%2815x%29
Inner: 2x+%2Asqrt%283x%29+%2A+%28-sqrt%285%29%29+=+-2x+%2Asqrt%2815x%29
Inner times inner and outer times outer actually subtract out.

Last: -sqrt%285%29%2A+sqrt%285%29+=+-5

Final answer: 12x%5E3+-+5

Many or all of these steps can be done in your head when you get some practice at these types of problems.

See my lesson plans on Radicals from Basic Algebra for more practice on these.

R^2 at SCC