Question

Find a linear equation whose graph is the straight line with the given property. HINT [See Example 2.]
Through (2, −3) and (1, 1)

Which formula do I use?
y2-y1/x2-x1 or y-y1=m(x-x1)[<--if i use this how do i plug in the numbers?]

Thank you.

Answer 1

Use both formulas.

m = (y2 - y1)/(x2 - x1)
= [1 - (-3)]/(1 - 2)
= (1 + 3)/(1 - 2)
= 4/-1 or -1/4

Substitute the first ordered pair into the second formula:

y - (-3) = -1/4(x - 2)
y + 3 = -1/4x + 2/4
y = -1/4x + 2/4 - 3
y = -1/4x - 10/4
This equation is in the form: y = mx+b

I hope this helps.