Hi Cor;
24x^{2}+48x+72=0
Both coefficients 24 and 48, as well as the constant 72, are multiples of 24. Henceforth, 24 can be factored out...
24(x^{2}2x3)=0
Let's divide both sides by 24...
[24(x^{2}2x3)]=0/24
x^{2}2x3=0
I did this to illustrate my point that the coefficient of 24 is no longer necessary to resolve this.
Let's factor.
For the FOIL...
FIRST must be (x)(x)=x^{2}
OUTER and INNER must addup to2x.
(x1)(x1)
Let's FOIL...
FIRST...(x)(x)=x^{2}
OUTER...(x)(1)=1x=x
INNER...(1)(x)=1x=x
LAST...(1)(1)=1
x^{2}xx+1
x^{2}2x+1
Obviously, we wanted the constant to be 3, not +1. The difference is 4...
[(x1)(x1)]4=0
(x1)^{2}=4
Let's square root both sides..
√[(x1)^{2}=√4
x1=2
x=3
Because (x1)^{2} has the same result as [(x1)^{2}], we must consider such...
(x1)=2
x+1=2
x1=2
x=1
********************************
3x^{2}30x+63=0
3(x^{2}10x+21)=0
x^{2}10x+21=0
(x7)(x3)=0
x7=0
x=7
x3=0
x=3
2/4/2014

Vivian L.
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