Answer: y = 2x - 5
Explanation:
Method I:
▪︎ Slope: m = (y2 - y1) / (x2 - x1)
▪︎ b is where the graph crosses the y-axis
▪︎ Points: (1, -3), (2, -1)
▪︎ m = (-1 - (-3)) / (2 - 1) = (3 - 1) / (1) = 2
▪︎ b = -5
▪︎ => y = 2x - 5
Method II:
▪︎ y = mx + b
▪︎ Points: (1, -3), (2, -1)
▪︎ System of equations:
-3 = m*1 + b,
-1 = m*2 + b
-3 = m + b,
-1 = 2m + b
m = -b - 3,
-1 = 2(-b - 3) + b
m = -b - 3,
-1 = -2b - 6 + b
m = -b - 3,
-1 + 6 = -2b + b
m = -b - 3,
5 = -b
m = -(-5) - 3,
b = -5
m = 2,
b = -5
▪︎ => y = 2x - 5