Question 22·Easy·Linear Functions
What is the slope of the line that passes through the points and ?
For slope-from-two-points questions, immediately write the slope formula , label one point as and the other as , and be careful to keep the order consistent in both numerator and denominator. Compute each difference separately, form the fraction, and then simplify it; this minimizes sign mistakes and makes these problems very quick to solve accurately on the SAT.
Hints
Write the slope formula
Think about how you normally compute the slope between two points. Write it as "change in over change in " using the coordinates.
Choose and label the points
Decide which point will be and which will be , and keep that order the same in both the numerator and denominator.
Compute and simplify
Find and , form the fraction, and then simplify it by dividing the numerator and denominator by their greatest common factor.
Desmos Guide
Use Desmos to compute the slope expression
In a Desmos expression line, type (6-3)/(4-(-2)) and press Enter. The numerical value Desmos gives you is the slope between the points and ; match this value to the closest fraction choice.
Step-by-step Explanation
Recall the slope formula
The slope of a line passing through two points and is given by
This is "change in over change in " (rise over run).
Label the points and find the changes
Let be and be .
- Change in :
- Change in :
Form the ratio and simplify to get the slope
Now plug these into the slope formula:
Simplify by dividing the top and bottom by :
So, the slope of the line is , which corresponds to choice A.