Реши уровнения и выполни проверку. Х•(75:5)=60. 15•3:х=9. k+120:4=500

Решите задачу:

$x \times (75 \div 5) = 60 \\ x \times 15 = 60 \\ 15x = 60 \\ x = 4 \\ 4 \times (75 \div 5) = 60$

$15 \times 3 \div x = 9 \\ \frac{15 \times 3}{x} = 9 \\ \frac{45}{x} = 9 \\ x =5 \\ 15 \times 3 \div 5 = 9$

$k + 120 \div 4 = 500 \\ k + 30 = 500 \\ k = 470 \\ 470 + 120 \div 4 = 500$