SOLUTION: Simplify. 4√3 - 1 / 2√3 + 2

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Question 378084: Simplify.
4√3 - 1 / 2√3 + 2

Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
4sqrt%283%29+-+1%2F2sqrt%283%29+%2B+2
If your problem is 4sqrt%283%29+-+1%2F%282sqrt%283%29+%2B+2%29 then a) put multiple term numerators and denominators in parentheses; and b) see the solution below.

First we'll rationalize the denominator of the middle term. Since there is just single term in the denominator this is fairly easy. We just multiply both the numerator and denominator by sqrt%283%29:
4sqrt%283%29+-+%281%2F2sqrt%283%29%29%28sqrt%283%29%2Fsqrt%283%29%29+%2B+2
giving us:
4sqrt%283%29+-+%281%2Asqrt%283%29%29%2F%282%2Asqrt%283%29%2Asqrt%283%29%29+%2B+2
which simplifies as follows:
4sqrt%283%29+-+sqrt%283%29%2F%282%2A3%29+%2B+2
4sqrt%283%29+-+sqrt%283%29%2F6+%2B+2
Then we can make all the denominators the same (so we can add and subtract):
24sqrt%283%29%2F6+-+sqrt%283%29%2F6+%2B+12%2F6
Adding and subtracting we get:
%2824sqrt%283%29+-+sqrt%283%29+%2B+12%29%2F6
The first two terms are like terms and can be subtracted:
%2823sqrt%283%29+%2B+12%29%2F6
Either this or 23sqrt%283%29%2F6+%2B+2 is the simplified answer.

If the problem was:
4sqrt%283%29+-+1%2F%282sqrt%283%29+%2B+2%29
Just like above we want to rationalize the second denominator. And just like above we will multiply the numerator and denominator to do so. The difference is that with a denominator of two terms it is not as easy to figure out what to multiply by. Our goal is to eliminate the square root in the denominator. So we have to figure out: "What can we multiply %282sqrt%283%29+%2B+2%29 that will cause the square root to disappear?" With two terms, the key is the pattern %28a%2Bb%29%28a-b%29+=+a%5E2+-+b%5E2. This shows us how to take a two-term expression, like a+b or a-b, and multiply it and get an expression of nothing but perfect square terms. Since %282sqrt%283%29+%2B+2%29 has a plus sign between the terms, we will use %282sqrt%283%29+-+2%29:

We'll use the Distributive Property to multiply the numerators. With the denominators we will just use the pattern:
4sqrt%283%29+-+%282sqrt%283%29+-+2%29%2F%28%282sqrt%283%29%29%5E2+-+2%5E2%29
which simplifies as follows:
4sqrt%283%29+-+%282sqrt%283%29+-+2%29%2F%284%2A3+-+4%29
4sqrt%283%29+-+%282sqrt%283%29+-+2%29%2F%2812+-+4%29
4sqrt%283%29+-+%282sqrt%283%29+-+2%29%2F8
The denominator is now rational. We can proceed to subtracting. First we need common denominators:
32sqrt%283%29%2F8+-+%282sqrt%283%29+-+2%29%2F8
Subtracting we get:
%2832sqrt%283%29+-+2sqrt%283%29+%2B+2%29%2F8
The first two terms in the numerator are like terms:
%2830sqrt%283%29+%2B+2%29%2F8
If we factor out a 2 in the numerator this fraction will reduce:
%282%2815sqrt%283%29+%2B+1%29%29%2F%282%2A4%29
%28cross%282%29%2815sqrt%283%29+%2B+1%29%29%2F%28cross%282%29%2A4%29
leaving"
%2815sqrt%283%29+%2B+1%29%2F4
This expression or 15sqrt%283%29%2F4+%2B+1%2F4 is the simplified expression.