Question

Найди значение выражения 21а/ab+b^2×(2/7+2b/7a), при а=5/9, b=8​

Answer 1

$\frac{21 \times \frac{5}{9} }{ \frac{5}{9} \times 8} + 8 {}^{2} \times ( \frac{2}{7} \times \frac{2 \times 8}{7 \times \frac{5}{9} } ) = \frac{ \frac{105}{9} }{ \frac{40}{9} } + 64 \times \frac{22}{5} = \frac{21}{8} + 64 \times \frac{22}{5} = \frac{533}{8} \times \frac{22}{5} = \frac{5863}{20} = 293.15$