Answer:
y = - 10
Step-by-step explanation:
Given that y varies directly with x then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 2 when x = - 4, that is
2 = - 4k ( divide both sides by - 4 )
[tex]\frac{2}{-4}[/tex] = k, that is
k = - [tex]\frac{1}{2}[/tex]
y = - [tex]\frac{1}{2}[/tex] x ← equation of variation
When x = 20, then
y = - [tex]\frac{1}{2}[/tex] × 20 = - 10
