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

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

$y = 1.5$