Factor out what is common in this equation first.
Then do the backwards FOIL method.
= 2 (9x^2 + 12 xy - 5y^2)
= 2 (3x - y)(3x + 5y)
2007-07-20 12:03:56
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answer #1
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answered by Reese 4
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Factor out 2 to start --> 18x^2 + 24 xy -10y^2 = 2*[9x^2 +12 xy - 5 y^2] = 2*((3x+5)(3x-1))
2007-07-20 19:05:32
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answer #2
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answered by nyphdinmd 7
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First step is ALWAYS to factor out a common term.
18, 24, & 10 are all divisible by 2
2[9x^2+12xy-5y^2]
use the ac method to find two factors that multiply to -45 and add up to +12
15*(-3) =-45
15+(-3) =+12
2[9x^2+15xy-3xy-5y^2] replace +12xy with +15xy-3xy
2[(9x^2+15xy)-(3xy+5y^2)]factor by grouping
2[3x(3x+5y)-y(3x+5y)]factor
2(3x+5y)[3x-y]factor out a common term
2(3x+5)(3x-y) solution
2007-07-20 19:12:18
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answer #3
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answered by bedbye 6
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ok: simplify to
2(9x^2 +12xy - 5y^2)
factor what's in the brackets, lets start with 9x^2, and guess even factors of 3x
so: (3x )(3x ), now we know the last terms must multiply to give 5y^2, and as 5 is prime we know the last terms are y and 5y so:
(3x 1y)(3x 5y) now we just need the signs, knowing that one is negative and one positive (as the term is -5y^2)...so using FOIL
if we expand with -y and +5y we get
(3x-y)(3x+5y)= 9x^2 +15xy -3xy - 5y^2)=(9x^2 +12xy -5y^2)
Which is what we are after....so fully factored it is:
2(3x-y)(3x+5y)
hope that the explaination makes sense to you!
2007-07-20 19:11:30
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answer #4
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answered by someguy_in_halifax 3
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18x^2 + 24xy - 10y^2
= 2 (9x^2 + 12xy - 5y^2)
= 2 (9x^2 - 3xy + 15xy - 5y^2)
= 2 [3x (3x - y) + 5y (3x - y) ]
= 2 (3x-y) (3x + 5y)
2007-07-20 19:08:39
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answer #5
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answered by Aditi 1
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2(9x^2+12xy-5y^2)
2(3x+5y)(3x-1y)
2007-07-20 19:04:06
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answer #6
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answered by D J 3
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