SOLUTION: (sqrt7-sqrt11)(2sqrt7+3sqrt11) I tried to foil but I don't understand the square root equality. I keep trying but I can't help thinking that I keep on getting the wrong answer.

Algebra ->  Algebra  -> Radicals -> SOLUTION: (sqrt7-sqrt11)(2sqrt7+3sqrt11) I tried to foil but I don't understand the square root equality. I keep trying but I can't help thinking that I keep on getting the wrong answer.       Log On

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Question 29284: (sqrt7-sqrt11)(2sqrt7+3sqrt11)
I tried to foil but I don't understand the square root equality. I keep trying but I can't help thinking that I keep on getting the wrong answer.
Thanks!
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
+%28sqrt7-sqrt11%29%282sqrt7%2B3sqrt11%29+

+%28sqrt%287%29%2A2sqrt%287%29%29+%2B+%28sqrt%287%29%2A3sqrt%2811%29%29+-+%28sqrt%2811%29%2A2sqrt%287%29%29+-+%28sqrt%2811%29%2A3sqrt%2811%29%29+
+%282sqrt%287%29%2Asqrt%287%29%29+%2B+%283sqrt%287%29%2Asqrt%2811%29%29+-+%282sqrt%2811%29%2Asqrt%287%29%29+-+%283sqrt%2811%29%2Asqrt%2811%29%29+
+2%2A7+%2B+3sqrt%287%2A11%29+-+2sqrt%2811%2A7%29+-+3%2A11+
+14+%2B+3sqrt%2877%29+-+2sqrt%2877%29+-+33+
+-19+%2B+3sqrt%2877%29+-+2sqrt%2877%29+ --> how many sqrt%2877%29s are there?... there are 3 minus 2 of them...answer is 1 of them:

+-19+%2B+sqrt%2877%29+
or
+sqrt%2877%29+-19+

jon.