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04.09.2014, 18:57
1) 3/(x+7)= 2/(9-x)
2/(9-x)=-2/(x-9)
3/(x+7)=-2/(x-9)
3/(x+7)-2/(9-x)=0
(5x-13)/((x-9)*(x+7))=0
1/(x-9)=0
1/(x+7)=0
5x=13
x=13/5
ОТВЕТ:x=13/5
2) 4+1/x-2=2+x/1+x
4+1/x-2=2x+1/x
2+x/1+x=2(x+1)
2x+1/x=2*(x+1)
1/x+2=2x+2
-2x=-1/x
-2x^2-1/x=0
1/x=0
2x^2=1
√2x-1/√2=0
√2x=1
√2x+1/√2=0
√2x=-1
x=-1/√2, x=1/√2
ОТВЕТ:x=-1/√2, x=1/√2
3) x+5/3=5/3+x
3x+5/3=3x+5/3 ==> (3x+5)*3=3*(3x+5)
x∈(-∞, ∞)
ОТВЕТ:x∈(-∞, ∞)
4) x/x-3-4/3-x=0
x/(x-3)-4/(3-x)=x+4/(x-3)
x+4/(x-3)=0
1/(x-3)=0
x=-4
ОТВЕТ:x=-4
Оценка: 1.5 (голосов: 6)
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