SOLUTION: Multiply (4√(5)-12√(7))*(5√(5)+15√(7)) I honestly don't even know where to start!!

Algebra ->  Square-cubic-other-roots -> SOLUTION: Multiply (4√(5)-12√(7))*(5√(5)+15√(7)) I honestly don't even know where to start!!      Log On


   

Question 387743: Multiply
(4√(5)-12√(7))*(5√(5)+15√(7))
I honestly don't even know where to start!!
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
%284sqrt%285%29+-+12sqrt%287%29+%29%2A%285sqrt%285%29+%2B+15sqrt%287%29+%29
Multiply the terms the same as in any multiplication of binomials. FOIL, etc.
= 4%2A5%2Asqrt%2825%29+%2B+4%2A15%2Asqrt%2835%29+-+60sqrt%2835%29+-180sqrt%2849%29
= 20%2A5+%2B+60sqrt%2835%29+-+60+sqrt%2835%29+-+180%2A7
= 100 - 1260
= -1160