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assuming the usual carelessness with parentheses, I get
(2x+10)/(x+5) = 2(x+5)/(x+5) = 2
(x^2-25)/(3x-15) = (x+5)(x-5) / 3(x-5) = (x+5)/3
(x^2+4x)/(x^2-9x) = x(x+4) / x(x-9) = (x+4)/(x-9)
(n^2+7n+10)/(n^2+2n-15)
= (n+2)(n+5) / (n-3)(n+5)
= (n+2)/(n-3)