\(B=\frac{1.2+2.4+3.6+4.8+5.10}{3.4+6.8+9.12+12.16+15.20}\\ =\frac{2+8+18+32+50}{12+48+108+192+300}\\ =\frac{110}{660}=\frac{1}{6}\)
B=\(\dfrac{1.2+1.2.4+1.2.3.3+1.2.2.8+1.2.5.5}{3.4+3.4.2.2+3.4.3.3+3.4.2.8+3.4.5.5}\)
B=\(\dfrac{1.2\left(4+3^2+2.8+5^2\right)}{3.4\left(2^2+3^2+2.8+5^2\right)}\)
B=\(\dfrac{1.2}{3.4}=\dfrac{1}{6}\)
Sau khi rút gọn biểu thức B, ta có:
B= \(\dfrac{\left[1.2\left(1+2+3+4+5\right)\right]}{\left[3.4\left(1+2+3+4+5\right)\right]}\)
B= \(\dfrac{1}{6}\)