SOLUTION: Please help me with this problem. I do not know how to do the radical sign on my keyboard. But the problem states: Multiply (2 radical sign 3 - 6radical sign 7)(4 radical si

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Please help me with this problem. I do not know how to do the radical sign on my keyboard. But the problem states: Multiply (2 radical sign 3 - 6radical sign 7)(4 radical si      Log On


   



Question 150430: Please help me with this problem. I do not know how to do the radical sign on my keyboard. But the problem states:
Multiply
(2 radical sign 3 - 6radical sign 7)(4 radical sign 3 + 12 radical sign 7)
I hope that someone can understand and help me with this problem. Thank you for your assistance.

Found 2 solutions by stanbon, vleith:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
(2 radical sign 3 - 6radical sign 7)(4 radical sign 3 + 12 radical sign 7)
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(2sqrt(3) - 6sqrt(7))*(4sqrt(3) + 12sqrt(7))
Use FOIL to multiply:
F: 2sqrt3*4sqrt3 = 8*3 = 24
O: 2sqrt3*12sqrt7 = 24sqrt21
I: -6sqrt7*4sqrt2 = -24sqrt
L: -6sqrt(7)*12sqrt(7) = -72*7 = -504
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Add these four terms to get: 24-504 = 480
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Cheers,
Stan H.

Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
Given: %282%2Asqrt%283%29+-+6%2Asqrt%287%29%29+%2A+%284%2Asqrt%283%29+%2B+12%2Asqrt%287%29%29
Use the 'normal method' for expanding via distribution.

Now simplify each term

The two terms in the middle cancel each other out in this case
24+-+504
-480