abigail and spencer

Question

Abigail and Spencer calculate the slope of the line between the points (3,-1) and (5,4) in different ways. Abigail calculates the slope by dividing -1 - 4 with 3 - 5. Spencer divides 4 - (-1) by 5 - 3. When they check their work with their mutual friend Lauren, she says that they are both wrong and shows them her work. She calculates -1 - 4 and divides by 5 - 3. Who is correct among these three friends? Who is incorrect? Why?

 

Answer 1

The correct formula for slope is

m = (y₂ - y₁) / (x₂ - x₁)

x₁ = 3

y₁ = -1

x₂ = 5

y₂ = 4

Plug in the numbers, evaluate, and you will get the correct answer.