75 times 3 =225
(x+15)(x+15) because if you multiply the 3 and 75 to get a number on the top of a diamond problem, and then on the bottom is 30, and 15+15 =30, and 15 times 15 =225, so therefore it has to be (x+15)(x+15)
2007-01-09 17:31:42
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answer #1
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answered by Anonymous
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Method 1: we can simplify 3x^2+30x+75 by taking the common term 3 and write it as 3(x^2+10x+25)
by looking at this we understand that u can compare this with a^2+2ab+b^2=(a+b)^2
where a=x and b=5
so we can write this as 3(x+5)^2.
method 2:for factorisation the basic clue is,
consider general term ax^2+bx+c and the expression 3x^2+30x+75.
here a=3,b=30,c=75
1.u have to find the product of the extreme terms=a x c.
in this case it is 3x 75=225
2. u have to work out combination of 2 numbers to add/subtract , so that u can arrive at the middle term b as well as get the value of(a x c)
here b=30, u can split 30 into 15 and 15 so their product (15 x 15) is the value of(3 x 75)
3.now the expression is writen as
3x^2+15x+15x+75
taking the common terms out we cxan simplify this as
3x(x+5)+15(x+5)
1.e (3x+15)(x+5)
u cab further simplify this as 3(x+5)(x+5)=3(x+5)^2
2007-01-10 03:21:51
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answer #2
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answered by srinsrinsri 2
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1. First find the common factor, which would be 3
3(x^2+10x+25)
2. Then just factor it the one in ( )
3(x+5)(x+5) = 3(x+5)^2
2007-01-09 17:15:12
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answer #3
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answered by ShadowX 3
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look for the lcd, so it would be 3 making the new equation
3(x2+10x+25) find the product and sum p s product is x2 times 25 and sum is 10. what times what equals 10 and at the same time equals 25? 5 + 5=10 and multiply its 25
so T-time 3l (x+5)(x+5)=0 3=0 x= -5 x= -5
2007-01-09 17:16:43
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answer #4
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answered by playaxn1 2
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You know it has to be (3x + something)(x + something).
What are some factors of 75? 3x25 15 x 5
15 x 5 looks pretty useful.
(3x + 15)(x + 5) will work.
2007-01-09 17:13:31
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answer #5
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answered by ecolink 7
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fact out the 3
3^2/3=x^2
30x/3=10x
75/3=25
3(x^2+10x+25)
3(x+5)(x+5) or 3(x+5)^2
2007-01-09 17:19:17
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answer #6
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answered by myke_n_ykes 6
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