Tính hợp lí:
a. A= \(\left(\frac{112}{13.20}+\frac{112}{20.27}+\frac{112}{27.34}+.....+\frac{112}{62.69}\right)\): \(\left(-\frac{5}{9.13}-\frac{7}{9.25}-\frac{13}{19.25}-\frac{31}{19.69}\right)\)
b. B= \(\frac{2.2016}{1+\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+......+\frac{1}{1+2+3+4+.....+2016}}\)
c. C= \(\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\frac{5^{10}.7^3-25^5.49^2}{\left(125.7\right)^3+5^9.14^3}\)
Giúp mk vs nha! Mai mk phải nộp rùi
tks m.n nhìu