Question

A line passes through (4, 5) and (8, 9). Which equation best represents the line?

A. y = x + 1
B. y = 1
C. y = 2x + 1
D. y = 5x + 8

Answer 1

y = x + 1

Explanation:

I got the answer right on the test

Answer 2

slope (m) = change in Y over change in X

change in Y = 9-5 = 4
change in x = 8-4 = 4
slope = 4/4 = 1
m = 1

the y intercept (b) would be found by using the formula y = mx+b

find b by replacing y, m and x in the equation with one of the points and the calculated slope:

(4,5) x = 4, y = 5 and slope m = 1
5 = 1*4 +b
5 = 4+b
b = 5-4
b=1

so the equation of the line would be y = x +1
the answer is A