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

for direct variation y = kx or y/x = k

This means that for direct variation the ratio y/x is always the same for all pairs of x,y
y1 y2
so ------ = ------
x1 x2
y1 -9
here ------ = ----- = -3
x1 3
y2 27
and ------ = ------ = 3
x2 9

y1 y2
since ------ not equal to ------
x1 x2

so answer is FALSE