Answer:
a. y = 2x - 23
Step-by-step explanation:
coordinates: (7, -9) & (8, -7)
y = mx+b
m (slope) = rise/ run = (y2-y1) / (x2-x1)
=( -7 - (-9) ) / (8-7)
=(-7+9) / 1
= 2/1
= 2
therefore, y=2x + b
now to find (b):
taken coordinate, (7, -9):
y= 2x + b
substitute the coordinates:
-9 = 2 (7) + b
-9 = 14 + b
-9 - 14 = b
-23 = b
(*we'll get the same value of b for the other coordinate too)
therefore, y= 2x - 23
