\(B=-\frac{15}{7}-\frac{23}{2}=-\frac{30}{14}+\left(-\frac{161}{14}\right)=-\frac{191}{14}\)
(đúng đề ko?)
đề đúng là:
Làm tính trừ B=\(\frac{-15}{7}\)-\(\frac{23}{2}\)
\(B=-\frac{15}{7}-\frac{23}{2}\)
\(-\frac{15}{7}=-\frac{15\times2}{7\times2}=-\frac{30}{14}\)\(\frac{23}{2}=\frac{23\times7}{2\times7}=\frac{161}{14}\)\(B=-\frac{15}{7}-\frac{23}{2}=-\frac{30}{14}-\frac{161}{14}=-\frac{191}{14}\)