xy = K so K = 21
Find an equation of variation where y varies directly as x. One pair of values is y = 80 when x = 40
40
y = -5
y = kx: 10 = 37k so k = 10/37 and y = 10x/37
1
2
xy = K so K = 21
If y and x are related inversely, then the equation for y can be said to be:y = k/xTo find the constant k, substitute 12 for y and 6 for x (a pair of values that are known to satisfy the equation).y = k/x12 = k/612 X 6 = k72 = kThe value of the variation constant k is 72.
There is only one equation that is given in the question and that equation is not a direct variation.
The equation is xy = 5*9 = 45 Alternatively, y = 45/x
-2
4x= y
y = 10x
Find an equation of variation where y varies directly as x. One pair of values is y = 80 when x = 40
40
57