SOLUTION: Please help me solve and explain so I can help my son understand. 3 - 2 radical 11 / 2 + radical 11 Write the equation in simplified radical form.

Algebra ->  Radicals -> SOLUTION: Please help me solve and explain so I can help my son understand. 3 - 2 radical 11 / 2 + radical 11 Write the equation in simplified radical form.      Log On


   



Question 541279: Please help me solve and explain so I can help my son understand.
3 - 2 radical 11 / 2 + radical 11
Write the equation in simplified radical form.

Answer by AnlytcPhil(1806) About Me  (Show Source):
You can put this solution on YOUR website!
%282sqrt%2811%29%29+%2F%282+%2B+sqrt%2811%29%29

Form the conjugate of the denominator by the rule:

the conjugate of A + B is A - B.  You just change the sign
of the second term but keep the sign of the first term.

So the conjugate of the denominator 2+%2B+sqrt%2811%29 is
2+-+sqrt%2811%29.

Put this conjugate over itself like this: red%28%282-sqrt%2811%29%29%2F%282-sqrt%2811%29%29%29.

Since that red fraction just equals 1 we can multiply our express
by it and not change its numerical value, but change its form. So we multiply
by it:

%282sqrt%2811%29%29+%2F%282+%2B+sqrt%2811%29%29×red%28%282-sqrt%2811%29%29%2F%282-sqrt%2811%29%29%29.

We'll put parentheses around the binomials:

%282sqrt%2811%29%29+%2F%28%282+%2B+sqrt%2811%29%29%29×red%28%28%282-sqrt%2811%29%29%29%2F%28%282-sqrt%2811%29%29%29%29.


And multiply numerators and denominators:










%284sqrt%2811%29-2%28sqrt%2811%29%29%5E2%29%2F%284-%28sqrt%2811%29%29%5E2%29+++++%29+++

%284sqrt%2811%29-2%2A11%29%2F%284-11%29%29+++++%29+++

%282%282sqrt%2811%29-11%29%29%2F%28-7%29%29+++++%29+++

To get the negative sign off the bottom, bring it to the top:

%28-2%282sqrt%2811%29-11%29%29%2F7%29+++++%29+++
 
We can multiply the negative sign into the parentheses so it won't
be sticking out in front:

%282%28-2sqrt%2811%29%2B11%29%29%2F7%29+++++%29+++

Finally we will reverse the terms in the parentheses:

%282%2811-2sqrt%2811%29%29%29%2F7%29+++++%29+++

That's the simplest form.  Or this way

2%2F7%2811-2sqrt%2811%29%29+++++%29+++

Edwin