y is directly proportional to x. When x = 4, y= 12.(a) Find the equation of y in term of x. (b) Find the value of y when x=7

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

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

Feel free to mark this as brainliest! :D

b) 36

step-by-step explanation:

18 times 2 is 36

62.5 paisa

step-by-step explanation:

4000*70 = 280000

280000-(2000*90) = 100000

4000-2400 = 1600

100000/1600 = 62.5

( give brainliest)