Toán Lớp 8: Tính
$4) \dfrac{x}{x+1}+\dfrac{-2x+1}{3(x+1)}$
$5) \dfrac{7}{x+5}+\dfrac{5-6x}{x(x+5)}$
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Toán Lớp 8: Tính
$4) \dfrac{x}{x+1}+\dfrac{-2x+1}{3(x+1)}$
$5) \dfrac{7}{x+5}+\dfrac{5-6x}{x(x+5)}$
Comments ( 2 )
4)
x/(x+1) + (-2x+1)/(3 (x+1))
= (3x + (-2x+1))/(3 (x+1))
= (3x – 2x + 1)/(3 (x+1))
= (x+1)/(3 (x+1))
= 1/3
5)
7/(x+5) + (5 -6x)/(x (x+5))
= (7x + (5-6x))/(x (x+5))
= (7x + 5 – 6x)/(x(x+5))
= (x+5)/(x (x+5))
= 1/x
4)x/(x+1)+(-2x+1)/(3(x+1))
=(3x)/(3(x+1))+(-2x+1)/(3(x+1))
=(3x-2x+1)/(3(x+1))
=(x+1)/(3(x+1))
=1/3
5)7/(x+5)+(5-6x)/(x(x+5))
=(7x)/(x(x+5))+(5-6x)/(x(x+5))
=(7x+5-6x)/(x(x+5))
=(x+5)/(x(x+5))
=1/x