Question

[ʚßồ Çôйǥ Ąйɦɞ]

Tìm x biết

a) \(\frac{3}{\left(x+2\right)\left(x+5\right)}\)+ \(\frac{5}{\left(x+5\right)\left(x+10\right)}\)+ \(\frac{7}{\left(x+10\right)\left(x+17\right)}\)= \(\frac{x}{\left(x+2\right)\left(x+17\right)}\)

Với x\(\notin\){-2;-5;-10;-17}

b) \(\frac{2}{\left(x-1\right)\left(x-3\right)}\)+ \(\frac{5}{\left(x-3\right)\left(x-8\right)}\)+ \(\frac{12}{\left(x-8\right)\left(x-20\right)}\)- \(\frac{1}{x-20}\)= \(\frac{-3}{4}\)

Với x \(\notin\){1,3,8,20}

c) \(\frac{x-1}{2009}+\) \(\frac{x-2}{2008}=\frac{x-3}{2007}+\frac{x-4}{2006}\)

Answer 1

[ho huu]

câu a;b: bạn áp dụng công thức \(\frac{a}{n.\left(n+a\right)}=\frac{1}{n+a}-\frac{1}{n}\left(a\inℕ^∗\right)\)