Question

1.Chứng minh rằng :

a) 1/a - 1/a + 1 =1/a x( a+1)

b)1/b - 1/b + m = m/b x(b+m)

c) 1/c x(c + m) - 1/ (c + m)x (c + 2m) = 2 x m/c x(c + m)x(c + 2m)

Giúp mình làm bài này với  

Answer 1

a) \(\frac{1}{a}-\frac{1}{a+1}=\frac{\left(a+1\right)-a}{a\cdot\left(a+1\right)}=\frac{1}{a\left(a+1\right)}\)(đpcm)

b) \(\frac{1}{b}-\frac{1}{b+m}=\frac{\left(b+m\right)-b}{b\left(b+m\right)}=\frac{m}{b\left(b+m\right)}\)(đpcm)