task/25037227
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1)
(y-b)² /(y-b+1) + (y-b) /(y-b+1) =((y-b)² +(y-b) ) /(y-b+1) =
(y-b)(y-b +1 ) /(y-b+1) = y-b.
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2)
(x² -y²)/(x-y+1) +(x+y) /(x-y+1) =(x -y)(x+y)/(x-y+1) +(x+y) /(x-y+1) =
(x+y) /(x-y+1) *(x -y +1) = x+y.
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3)
(a+x)²/(a+x-2) -(2a+2x) /(a+x-2) =(a+x)²/(a+x-2) -2(a+x) /(a+x-2) =
( (a+x)/(a+x-2) ) * (a+x-2) =a+x.
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4)
(b² -9c²)/(b+3c-2) +2(b-3c)/(2-b-3c) =(b²-(3c)²)/(b+3c-2)+2(b-3c)/(2-b-3c) =
(b-3c)(b+3c)/(b+3c-2)-2(b-3c)/(b+3c-2) =
( (b-3c) / (b+3c-2) )*(b+3c-2) =b-3c .