What is the substitution to 3x y=-16 5x y=-20?

The first one ,to substitute 3xy from -16 ...so divided both side by 3 .so, (xy =-5.33). the second one,5xy =-20. so,divided both sides by 5 so xy = -4

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.