Question

the value of y varies directly with x. If x equals 3 then y equals 21 what is the value of x when y equals 105.​

Answer 1

x = 15

Explanation:

The equation for direct variation is

y = kx

y=21 when x=3

21 = k*3

Divide each side by 3

21/3 = 3k/3

7 =k

y = 7x

Let y=105

105 = 7*x

Divide by 7

105/7 = x

15 =x