X is partly constant and partly varies as y . when y =2,x=15 and y =4, x=27 (a) find the formula which connects x and y (b) find x when y=7

looks like your standard:

x = my + b

case1: y = 2 when x = 15
15 = 2m + b **
case2: y = 4 when x = 27
27 = 4m + b ***

subtract ** from ***
12 = 2m
m=6
from ** 15 = 12+b ---> b=3

x = 6y + 3

when y = 7
x = 42+3 = 45

Fine the relationship between x&y

Your question is some how confusing explain in better tone

D is partly constant and partly varies with v, where v=40,

d=192. Find the formula connecting d and v, Calculate d when v=73.

If a is partly constant and partly varies with b when a =15 b=2 and when a=27 b=5 a) find the equation for this expression b)find the values of the two constant

I your cooperation

To find the formula that connects x and y, we can first observe that when y increases by a factor of 2 (from 2 to 4), x also increases by a factor of 1.8 (from 15 to 27). This suggests that there is a linear relationship between x and y.

(a) Finding the formula:
Let's assume the formula connecting x and y is of the form:

x = a * y + b

Using the given data, we can plug in the values for x and y to form two equations:

When y = 2,
x = 15
15 = a * 2 + b --(1)

When y = 4,
x = 27
27 = a * 4 + b --(2)

We now have a system of two linear equations. We can solve this system to find the values of 'a' and 'b'.

To eliminate 'b', we can subtract equation (1) from equation (2):

(27 - 15) = (a * 4 + b) - (a * 2 + b)
12 = 2a
a = 6

Next, substitute the value of 'a' into equation (1) to solve for 'b':

15 = (6 * 2) + b
15 = 12 + b
b = 3

Therefore, the formula connecting x and y is:
x = 6y + 3

(b) Finding x when y = 7:
Using the formula we found:
x = 6 * 7 + 3
x = 42 + 3
x = 45

So, when y = 7, x = 45.