Sau khi rút gọn biểu thức  \(\dfrac{{{5^{11}}{{.7}^{12}} + {5^{11}}{{.7}^{11}}}}{{{5^{12}}{{.7}^{12}} + {{9.5}^{11}}{{.7}^{11}}}}\) ta được phân số \(\dfrac{a}{b}.\) Tính tổng \(a + b.\)

\(\dfrac{{ - 2}}{4}\) 

\(\dfrac{{ - 15}}{{ - 96}}\)  

\(\dfrac{{13}}{{27}}\)

\(\dfrac{{ - 29}}{{58}}\)

\(\dfrac{{220}}{{240}};\dfrac{{225}}{{240}};\dfrac{{276}}{{240}}\)                            

\(\dfrac{{225}}{{240}};\dfrac{{220}}{{240}};\dfrac{{276}}{{240}}\)                     

\(\dfrac{{225}}{{240}};\dfrac{{276}}{{240}};\dfrac{{220}}{{240}}\)         

\(\dfrac{{220}}{{240}};\dfrac{{276}}{{240}};\dfrac{{225}}{{240}}\)

\(14\) 

\(23\)  

\(12\)

\(22\)

\(\dfrac{1}{2}\)                    

\(\dfrac{6}{8}\)          

\(\dfrac{3}{4}\)                 

\(\dfrac{{ - 3}}{4}\)

\(\dfrac{{16}}{{ - 18}}\) 

\(\dfrac{{ - 72}}{{81}}\)  

\(\dfrac{{ - 24}}{{ - 27}}\)      

\(\dfrac{{ - 88}}{{99}}\)

\(\dfrac{{ - 1}}{7}\) 

\(\dfrac{{ - 1}}{{14}}\)  

\(\dfrac{4}{{ - 56}}\)         

\(\dfrac{{ - 1}}{{70}}\)    

\(\dfrac{{ - 13}}{{25}}\)                   

\(\dfrac{{ - 18}}{{25}}\)         

\(\dfrac{{ - 6}}{{25}}\)

\(\dfrac{{ - 39}}{{50}}\)