Question

True or False? Y varies directly with x and y = -9 when x = 3. When y = 27, the value of x is 9.

Answer 1

Y varies directly with x
=> y = kx

y = -9 when x = 3
=> -9 = k(3)

Solve k

Then, solve x when y = 27

Answer 2

I dont know

Answer 3

Which part?

Answer 4

y= 27 the whole formula

Answer 5

Y varies directly with x
=> y = kx

^ Do you understand this part?

Answer 6

WAIT, -9 = k(3)

Answer 7

Then do I times 3 on both sides

Answer 8

Nope, to solve k, you need to divide 3 on both sides.

Answer 9

Oh wait, another little trick

Answer 10

-9 = k(3)

^ Multiply -3 to both sides, so that you can get 27 on the left. ( y=27 as given in the question)

Then, see if the coefficient of k is 9. If it is, then it is true, and vice versa.

Answer 11

OH ok thanks

Answer 12

Welcome :)