Respuesta :
Answer:
see explanation
Step-by-step explanation:
(a)
Given y is directly proportional to x then the equation relating them is
y = kx ← k is the constant of proportion
To find k use the condition when x = 4 , y = 12 , then
12 = 4k ( divide both sides by 4 )
3 = k
y = 3x ← equation of proportion
(b)
When x = 7 , then
y = 3 × 7 = 21
Answer:
a) y = 3x
b) y = 21
Step-by-step explanation:
a) y = kx
When x = 4, y = 12,
12 = k*4
k = 12/4
= 3
y = 3x
b) When x=7,
y = 3(7)
= 21
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