Question

Решите плиз срочно!!!​

Answer 1

$\displaystyle 1)1,5:5=x:3\\4,5=5x\\5x=4,5\\x=0,9\\\\ 2)42:x=21:2,x\neq 0\\84=21x\\21x=84\\x=4$

Answer 2

по правилу пропорции →

$\frac{1.5}{5} = \frac{x}{3} \\ 1.5 \times 3 = 5x \\ 5x = 4.5 \\ x = 4.5 \div 5 \\ x = 0.9 \\ = = = = = = = = =$

$\frac{42}{x} = \frac{21}{2} \\ 42 \times 2 = 21x \\ 21x = 84 \\ x = 84 \div 21 \\ x = 4$