Answer:
a) y = 2 x - 1
b) y = - x + 7
c) y = 7 x + 2
Explanation:
Use a pair of (x1, y1) and (x2, y2) points to find the equation of the line for each tables:
a) (5, 9) and (10, 19)
slope: (y2 - y1) / (x2 - x1) = (19 - 9) / (10 - 5) = 10 / 5 = 2
Then y = 2 x + b
solve for b in: 9 = 2 (5) + b
b = 9 - 10 = -1
Then y = 2 x - 1
b) (2, 5) and (5, 2)
slope: (y2 - y1) / (x2 - x1) = (2 - 5) / (5 - 2) = -3 / 3 = -1
Then y = - x + b
solve for b in: 5 = - (2) + b
b = 5 + 2 = 7
Then y = - x + 7
c) (3, 23) and (6, 44)
slope: (y2 - y1) / (x2 - x1) = (44 - 23) / (6 - 3) = 21 / 3 = 7
Then y = 7 x + b
solve for b in: 23 = 7 (3) + b
b = 23 - 21 = 2
Then y = 7 x + 2