Answers

2014-07-06T12:21:41+08:00
1. x(x+3-3)=0
2. 4(x2-25)=0
3. 2x2-13x+21=0
 Final answer: (x-3)(2x-7)
4. 4x(x-3)
5. 4x2-12+9=0
final answer: (2x-3)(2x-3)
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2014-07-06T12:26:55+08:00
Number 1:
 x^{2} +6x-6=0 (No factor)
 x^{2} +6x=6
 x^{2} +6x+(3)^2=6+(3)^2
 \sqrt{(x+3)^2}=+or- \sqrt{15}
x+3=+or- \sqrt{15}
x=+or- \sqrt{15} -3

Number 2:
4 x^{2} -100=0
(2x+10)(2x-10)=0
2x+10=0
\frac{2x}{2}= -\frac{10}{2}
x=-5
2x-10=0
 \frac{2x}{2} = \frac{10}{2}
x=5

Number 3:
2 x^{2} -13=-21
2 x^{2} -13x+21=0
(2x-7)(x-3)=0
2x-7=0
 \frac{2x}{2} = \frac{7}{2}
x= \frac{7}{2}
x-3=0
x=3

Number 4:
4 x^{2} -12=0
4x(x-3)=0
4x=0
x=0
x-3=0
x=3

Number 5:
4 x^{2} +9=12x
4 x^{2} -12x+9=0
(2x-3)^2=0
2x-3=0
 \frac{2x}{2} = \frac{3}{2}
x= \frac{3}{2}

(Sorry for the late answers... (: )

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