Find the expression for y. 1) x y=? 1 9 2 12 3 15 4 18 5 21 2) x y=? 1 -12 2 -17 3 -22 4 -27 5 -32 3) x y=? 1 -18 2 -12 3 -2 4 12 5 30

Answer 1

(x,y) = (0,6), (1,9), (2,12,) (3,15), (4,18), (5,21), (6,24), all lie on a straight line y= 3x+6

the y values are an arithmetic sequence with common difference = 3

2 (x,y) = (0,-7), (1,-12), (2,-17), (3,-22), (4,-27) ... all lie on a line y=-5x -7

3 (x,y) = (1,-18), (2,-12), (3,-2), (4,12), (5,30) are not on a straight line. the middle 3 points look like part of a parabola with vertex and maximum point (3,-2), but the (1,-18) and (5,30) points don't fit. Ignore the last point or change it to (5,-18) and the parabola would be y=a(x-3)^2 -2, -18=4a-2, a=-4 y=-4(x-3)^2-2