Bài 1:
a, $B= 158.(\frac{12-\frac{12}{7}-\frac{12}{289}-\frac{12}{85}}{4-\frac{4}{7}-\frac{4}{289}-\frac{4}{85} }:\frac{5+\frac{5}{13}-\frac{5}{169}-\frac{5}{91}}{6+\frac{6}{13}-\frac{6}{169}-\frac{6}{91}})$
= $158.[\frac{12.( 1-\frac{1}{7}-\frac{1}{289}-\frac{1}{85})}{4.( 1-\frac{1}{7}-\frac{1}{289}-\frac{1}{85}) }:\frac{5.( 1+\frac{1}{13}-\frac{1}{169}-\frac{1}{91}}{6.( 1+\frac{1}{13}-\frac{1}{169}-\frac{1}{91})}]$
= $158.(\frac{12}{4}:\frac{5}{6})$
= $158.\frac{12.6}{4.5}$
= $158.3,6$
= $568,8$
b, Mình chưa làm đc