If y varies directly as x, and y = 9 when x = 12, find the value of y when x = 7.?

Question

If y varies directly as x, and y = 9 when x = 12, find the value of y when x = 7.

Answer 1

So
Y = X + C

9 = 12 + C
C = -3

Y = X - 3
X = 7
Y = 4

Answer 2

If y varies directly as x, this means
that y = k * x, where k is a constant.

Plugging in the x and y values gives :
9 = k * 12
So, k = 9 / 12 = 3 / 4.

The general equation is therefore : y = (3 / 4)x

Now when x = 7,
y = (3 / 4) * 7
= 21 / 4

Answer 3

if the values go up and down in relation to each other and 9 is 3 less than 12 then when x is 7 then y will be again three less than that number which is y = 4

Answer 4

RE: If y varies at as quickly as with x, and y=10 whilst x=15, locate y whilst x=6.? If x varies inversely as y and x=2 whilst y=8, locate x whilst y=17. If y varies at as quickly as as x and inversely as z^2, and y=3 whilst x=2 and z=4, what's the fee of x whilst y=9 and z=4?

Answer 5

K=xy so
Y= K/X
so K=108(12*9)
Y=108/7
that is the answer

Answer 6

x α y
x = my
12 = 9m
m = 12/9
m = 4/3
when x = 7
7 = 4/3y
y = 21/4

Answer 7

y=5.25