Question

1-вариант Задание-1.(1 балл) Задана пропорция 2х : 20 = 5:40. Найдите значение x​

Answer 1

Первый способ:

$2x \div 20 = 5 \div 40 \\ \\ 2x \times 40 = 5 \times 20 \\ \\ 80x = 100 \\ \\ x = \frac{100}{80} = \frac{5}{4} =1 \frac{1}{4} = 1.25$

Второй способ:

$2x \div 20 = 5 \div 40 \\ \\ \frac{2}{20} x = \frac{5}{40} \\ \\ \frac{1}{10}x = \frac{1}{8} \\ \\ \frac{1}{10} x = 0.125 \\ \\ x = 1.25$

Третий способ:

$2x \div 20 = 5 \div40 \\ \\ \frac{1}{10}x = 0.125 \\ \\ \frac{1}{10} x - 0.125 = 0 \\ \\ x - 1.25 = 0 \\ \\ x = 1.25$

Четвёртый способ:

$2x \div 20 = 5 \div 40 \\ \\ 0.1x = 0.125 \\ \\ x = 0.125 \div 0.1 \\ \\ x = 1.25$