Answer:
(C) y = 3x
Step-by-step explanation:
Directly proportional relation is one in which the value of x and y gets increases or decreased in same proportion.
example of such relation can be y = kx
where k is the constant of proportionality which depicts by how much value of y will change in response to change of x.
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now in the option
A and B
y= 9 , y =1/5
value of y is constant and does not depend on other variable. it value will remain same.
for y = x+4
value of y increases with x but it does not increase proportionally.
let see an example for x =1 , y = 1+4 = 5
x =2 , y = 2+4 = 6
(1,5) and (2,6) are not proportionally changing also this equation is not of form y = kx
thus, it is incorrect option.
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(C) y = 3x
here equation is form y =kx . in place of k there is 3
let see an example for x =1 , y = 3*1 = 3
x =2 , y = 3*2 = 6
(1,3) and (2,6) are proportionally changing (1/3 = 2/6) also this equation is of form y = kx
thus, it is correct option.
