Cho $A = \frac{\frac{-1}{2} -5 \times \frac{3}{2}^{2}}{15\frac{2}{9} + (-\frac{2}{3})^{2}}

Ta có:

$A = \frac{\frac{- 1}{2} - 5 \times {\frac{3}{2}}^{2}}{15 \frac{2}{9} + (- \frac{2}{3})^{2}}$

= $A = \frac{\frac{- 1}{2} - 5 \times \frac{9}{4}}{\frac{137}{9} + \frac{4}{9}} = \frac{\frac{- 1}{2} - \frac{45}{4}}{\frac{47}{3}} = \frac{\frac{- 47}{4}}{\frac{47}{3}}$

$= \frac{- 47}{4} / \frac{47}{3} = \frac{- 3}{4} .$

$B = \frac{7}{12} \times 3.4 - \frac{7}{12} \times 8.8 .$

$= \frac{7}{12} \times (3.4 - 8.8) = \frac{7}{12} \times (- 5.4) = \frac{7}{12} \times \frac{- 27}{5} = \frac{- 63}{20} .$

Do đó $A - 5 B = \frac{- 3}{4} - 5 \times \frac{- 63}{20} = \frac{- 3}{4} + \frac{63}{4} = 15$

Cho $A = \frac{\frac{-1}{2} -5 \times \frac{3}{2}^{2}}{15\frac{2}{9} + (-\frac{2}{3})^{2}}

Bài học cùng chủ đề

Đề thi cùng chủ đề