Question

find the value of x such that (Tìm x biết ) :   \(\frac{x+7}{\left(a+1\right)\left(a+7\right)}=\frac{1}{a+1}-\frac{1}{a+7}\)

( a khác -1; -7 )

Answer 1

\(\frac{1}{a+1}-\frac{1}{a+7}=\frac{a+7}{\left(a+1\right)\left(a+7\right)}-\frac{a+1}{\left(a+1\right)\left(a+7\right)}=\frac{6}{\left(a+1\right)\left(a+7\right)}\)

=>x+7=6

=>x=6-7

=>x=-1

vậy x=-1

Answer 2

\(\frac{1}{a+1}-\frac{1}{a+7}=\frac{\left(a+7\right)-\left(a+1\right)}{\left(a+1\right)\left(a+7\right)}=\frac{6}{\left(a+1\right)\left(a+7\right)}\)=> x + 7 = 6 => x = -1

Answer 3

r`, h thì hỉu -_-