1)
а) 2a/7b.
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б) 3/(x+4) .
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в) (y² -z²)/(2y+2z) =(y-x)(y+x)/2(y+z) =(y-z)/2.
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2)
а) (3x-1)/x² +(x-9)/3x =(3(3x-1) +x(x-9))/3x² =(9x-3+x²-9x)/3x² =(x²-3)/3x²
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б) 1/(2a-b)-1/(2a+b) =(2a+b-(2a -b))/(2a-b)(2a+b) =(2a+b-2a +b))/(2a-b)(2a+b)= 2b/(4a² -b²).
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в) 5/(c+3) -(5c-2)/(c²+3c) =.5/(c+3) -(5c-2)/(c(c+3)=.(5c -5c+2)/c(c+3) =2/c(c+2). || 2c/(c²+2c)
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3) (a² -b)/a -a =(a² -b -a²)/a = -b/a = -(5)/0,2 =5/0,2 = 50/2 =25.
3/(x-3) -(x+15)/(x² - 9) -2/x = (3x(x+3) -x(x+15) - 2(x² -9))/x(x² -9) =
(3x²+9x -x² -15x - 2x²+18)/x(x²-9) = - 6(x-3)/x(x-3)(x+3) = -6/(x²+3x).