a,
\(1=\frac{5}{x}=\frac{x}{12}\)
+) \(1=\frac{5}{x}\)
=> 1.x = 5.1
=> x = 5
+) \(1=\frac{x}{12}\)
=> 1.12 = x.1
=> x = 12
vậy ta có :
\(1=\frac{5}{5}=\frac{12}{12}\)
b,
\(0=\frac{x}{7}=\frac{x}{85}\)
+) \(0=\frac{x}{7}\)
=> 0.7 = 1.x
=> x = 0
+) \(0=\frac{x}{85}\)
=> 0.85 = 1.x
=> x = 85
vậy ta có \(0=\frac{0}{7}=\frac{0}{85}\)