All PSAT Math Resources
Example Questions
Example Question #1 : How To Find The Slope Of Parallel Lines
In the xy-plane, what is the equation for a line that is parallel to and passes through the point ?
In order to solve the equation for this line, you need to things: the slope, and at least one point. You are already given a point for the line, so you just need to figure out the slope. The other piece of information you have is a line parallel to the line that you're looking for; since parallel lines have the same slope, you just need to figure out the slope of the parallel line you've already been given.
To figure out the slope, change the equation into point-slope form (y = mx+b) so the slope m is easy to find. To do that, you need to isolate y on one side of the equation.
By the calculations above, you'll find that the slope of the parallel line is -1/2.
Now, use this slope of -1/2 and the point 4,1 to find the equation. First, plug them both into the point-slope form, then solve for the slope-intercept form.
Example Question #1 : Coordinate Geometry
Which of the following is the equation of a line that is parallel to the line 4x – y = 22 and passes through the origin?
4x = 8y
4x + 8y = 0
y – 4x = 22
4x – y = 0
(1/4)x + y = 0
4x – y = 0
We start by rearranging the equation into the form y = mx + b (where m is the slope and b is the y intercept); y = 4x – 22
Now we know the slope is 4 and so the equation we are looking for must have the m = 4 because the lines are parallel. We are also told that the equation must pass through the origin; this means that b = 0.
In 4x – y = 0 we can rearrange to get y = 4x. This fulfills both requirements.
Example Question #1 : Coordinate Geometry
What line is parallel to 2x + 5y = 6 through (5, 3)?
y = 3/5x – 2
y = 5/2x + 3
y = 5/3x – 5
y = –2/5x + 5
y = –2/3x + 3
y = –2/5x + 5
The given equation is in standard form and needs to be converted to slope-intercept form which gives y = –2/5x + 6/5. The parallel line will have a slope of –2/5 (the same slope as the old line). The slope and the given point are substituted back into the slope-intercept form to yield y = –2/5x +5.
Example Question #3 : Coordinate Geometry
What line is parallel to through ?
The slope of the given line is and a parallel line would have the same slope, so we need to find a line through with a slope of 2 by using the slope-intercept form of the equation for a line. The resulting line is which needs to be converted to the standard form to get .
Example Question #114 : Psat Mathematics
Find the equation of a line parallel to that also passes through the point .
Since they are parallel, the line will have the same slope as .
Thus, it will take the form .
We then use the point (3,2) to solve for :
so the equation of the line is
Example Question #1 : How To Find The Equation Of A Parallel Line
In the -plane, the line is parallel to the line . What is the value of ?
In this equation, is equal to the slope of the line. You have been given a line parallel to the line containing variable , and since parallel lines have the same slope, all you need to do is figure out the slope of in order to figure out what is. To figure out the slope of , you need to convert the equation into form, which means isolating on one side of the equation.
Given this solution, the slope of the parallel lines, and thus , is equal to 2.
Example Question #1 : How To Find The Equation Of A Parallel Line
Which of the following lines has zero points of intersection with the line, ?
This prompt asks you to find a line that is parallel to the one given. Parallel lines have no points of intersection (as opposed to intersecting lines which have 1 point of intersection). Parallel lines have the same slope, but different y-intercepts. If they had the same y-intercept, then they would actually be the same line.
We can find the slope of the first line by converting it to slope-intercept form.
First, subtract 3x from both sides.
Then, divide both sides by -2.
The slope of the line is 3/2. The only answer that has that same slope, but a different y-intercept is .
Example Question #1 : How To Graph A Line
A line graphed on the coordinate plane below.
Give the equation of the line in slope intercept form.
The slope of the line is and the y-intercept is .
The equation of the line is .
Example Question #2 : Graphing
Give the equation of the curve.
None of the other answers
This is the parent graph of . Since the graph in question is negative, then we flip the quadrants in which it will approach infinity. So the graph of will start in quadrant 2 and end in 4.
Example Question #2 : Graphing
The equation represents a line. This line does NOT pass through which of the four quadrants?
Cannot be determined
IV
II
I
III
III
Plug in for to find a point on the line:
Thus, is a point on the line.
Plug in for to find a second point on the line:
is another point on the line.
Now we know that the line passes through the points and .
A quick sketch of the two points reveals that the line passes through all but the third quadrant.