Question

решить уравнение 21/b = 0,7/0,8 , 7:10 = 140 : n , 0,7/0,9 = 14/a , 5,1/y = 1,7/0,5​

Answer 1

$\frac{21}{b} = \frac{0.7}{0.8} \\ \frac{21}{b} = \frac{7}{8} \\ 7b = 21 \times 8 = 168$b=168:7

b=24

$7 \div 10 = 140 \div n \\ 140 \div n = 0.7 \\ n = 140 \div 0.7 = 1400 \div 7 \\ n = 200$

$\frac{0.7}{0.9} = \frac{14}{a} \\ 0.7a = 0.9 \times 14 = 12.6 \\ a = 12.6 \div 0.7 = 126 \div 7$

a=18

$\frac{5.1}{y} = \frac{1.7}{0.5} \\ 1.7y = 5.1 \times 0.5 = 2.55 \\ y = 2.55 \div 1.7 = 25.5 \div 17$

$y = 1.5$