SOLUTION: Multiply (3*SQRT(2)-9*SQRT(6))*(5SQRT(2)+15*SQRT(6))

Algebra ->  Square-cubic-other-roots -> SOLUTION: Multiply (3*SQRT(2)-9*SQRT(6))*(5SQRT(2)+15*SQRT(6))      Log On


   

Question 352223: Multiply
(3*SQRT(2)-9*SQRT(6))*(5SQRT(2)+15*SQRT(6))
Found 2 solutions by Fombitz, sofiyac:
Answer by Fombitz(32388) About Me  (Show Source):
Answer by sofiyac(983) About Me  (Show Source):
You can put this solution on YOUR website!
%283%2Asqrt%282%29-9%2Asqrt%286%29%29%2A%285%2Asqrt%282%29%2B15%2Asqrt%286%29%29
ok, in order to simplify this problem we use distributive property
%28a-b%29%28c%2Bd%29=ac%2Bad-bc-bd
now you simplify

simplify further, for example sqrt%282%29%2Asqrt%282%29=sqrt%282%2A2%29=sqrt%284%29=2, so we have
15%2A2%2B45%2Asqrt%2812%29-45%2Asqrt%2812%29-135%2A6%29

30%2B45%2Asqrt%2812%29-45%2Asqrt%2812%29-810%29 Notice that the two terms in the middle are the same with opposite signs so they add to zero, thus you get
30-810=-780