Question

Прошу, помогите с простенькими уравнениями
1. x+3/5=13/20

2. x-3/20=4/5-1/2

Answer 1

1. x+3/5=13/20 |×20
4х+12=13
4х=1
х= 0,25
Ответ: х=0,25

2. x-3/20=4/5-1/2
x-3/20=3/10 |×20
х-3= 6
х=9
Ответ:х=9

Answer 2

$x + frac{3}{5} = frac{13}{20} \ x + frac{4 times 3}{4 times 5} = frac{13}{20} \ x + frac{12}{20} = frac{13}{20} \ x = frac{13}{20} - frac{12}{20} \ x = frac{1}{20} = frac{5}{100} = 0.05$
$x - frac{3}{20} = frac{4}{5} - frac{1}{2} \ x - frac{3}{20} = frac{4 times 4}{5 times 4} - frac{1 times 10}{2 times 10} \ x - frac{3}{20} = frac{16 - 10}{20} \ x - frac{3}{20} = frac{6}{20} \ x = frac{6 + 3}{20} = frac{9}{20} = frac{45}{100} = 0.45$