Which equations show direct variation between x and y? Choose all answers that are correct. a 3x=7 b y=4.2/x c y/x=6 d y=0.5x + 9

a). No. Variation in 'y' has no effect on 'x'.

b). No. Variation in 'x' has exactly the opposite effect on 'y'.

c). Yes. Variation in 'x' causes 'y' to vary 6 times as much in the same direction.

d). No. Doubling 'x' does not double 'y'.