All SAT Math Resources
Example Questions
Example Question #2 : How To Find The Equation Of A Line
What is the equation of a line that passes through coordinates and ?
Our first step will be to determing the slope of the line that connects the given points.
Our slope will be . Using slope-intercept form, our equation will be . Use one of the give points in this equation to solve for the y-intercept. We will use .
Now that we know the y-intercept, we can plug it back into the slope-intercept formula with the slope that we found earlier.
This is our final answer.
Example Question #21 : How To Find The Equation Of A Line
Which of the following equations does NOT represent a line?
The answer is .
A line can only be represented in the form or , for appropriate constants , , and . A graph must have an equation that can be put into one of these forms to be a line.
represents a parabola, not a line. Lines will never contain an term.
Example Question #7 : How To Find The Equation Of A Line
Let y = 3x – 6.
At what point does the line above intersect the following:
(–3,–3)
(–5,6)
They intersect at all points
(0,–1)
They do not intersect
They intersect at all points
If we rearrange the second equation it is the same as the first equation. They are the same line.
Example Question #22 : How To Find The Equation Of A Line
Find the equation of a line that goes through the points , and .
For finding the equation of a line, we will be using point-slope form, which is
, where is the slope, and is a point.
We will pick the point
If we picked the point
We get the same result
Example Question #23 : How To Find The Equation Of A Line
Find the equation of a line that passes through the point , and is parallel to the line .
Since we want a line that is parallel, we will have the same slope as the line . We can use point slope form to create an equation.
, where is the slope and is a point.
Example Question #24 : How To Find The Equation Of A Line
Find the equation of the line shown in the graph below:
y = 2x + 4
y = -1/2x - 4
y = -1/2x + 4
y = x/2 + 4
y = x/2 + 4
Based on the graph the y-intercept is 4. So we can eliminate choice y = x/2 - 4.
The graph is rising to the right which means our slope is positive, so we can eliminate choice y = -1/2x + 4.
Based on the line, if we start at (0,4) and go up 1 then 2 to the right we will be back on the line, meaning we have a slope of (1/2).
Using the slope intercept formula we can plug in y= (1/2)x + 4.