SOLUTION: Multiply {{{(3*sqrt(2)-6*sqrt(5))(4*sqrt(2)+8*sqrt(5))}}}

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Multiply {{{(3*sqrt(2)-6*sqrt(5))(4*sqrt(2)+8*sqrt(5))}}}      Log On


   

Question 224811: Multiply %283%2Asqrt%282%29-6%2Asqrt%285%29%29%284%2Asqrt%282%29%2B8%2Asqrt%285%29%29
Found 2 solutions by RAY100, LtAurora:
Answer by RAY100(1637) About Me  (Show Source):
You can put this solution on YOUR website!
(3sqrt2 -6sqrt5)(4sqrt2+8sqrt5)
.
use distribution or FOIL
.
(3sqrt2)(4sqrt(2) +(3sqrt2)(8sqrt5)-(6sqrt5)(4sqrt2)-(6sqrt5)(8sqrt5)
.
{(3*4)(sqrt2*sqrt2)}+{(3*8)(sqrt2*sqrt5)}-{6*4)(sqrt5*sqrt2)} -{(6*8)(sqrt5*sqrt5)}
.
{12 sqrt4} + {24sqrt(10) - {24sqrt10} - {48sqrt25}
.
{12*2} +[0} - {48*5}
.
24 - 240
.
-216
.
.
Check,,,,use calc to est original,,,,ok
.


Answer by LtAurora(115) About Me  (Show Source):
You can put this solution on YOUR website!
%283%2Asqrt%282%29-6%2Asqrt%285%29%29%284%2Asqrt%282%29%2B8%2Asqrt%285%29%29
Factor this out:

Now, combine all the terms:
%283%2A4%2A2%29%2B%2824%2Asqrt%2810%29%29-%2824%2Asqrt%2810%29%29-%286%2A8%2A5%29
The middle terms cancel out and the first and last terms can be multiplied and then combined to yield:
24-240
=-216