Answer: 10
Step-by-step explanation:
varies directly means: [tex]\frac{y}{x} = k[/tex]
Step 1: solve for k ⇒ [tex]\frac{21}{5} = k[/tex]
Step 2: plug in the given value and k to solve for the missing value: [tex]\frac{42}{x} = \frac{21}{5}[/tex]
42(5) = 21(x)
[tex]\frac{42(5)}{21} = \frac{21(x)}{21}[/tex]
2(5) = x
10 = x
