All ACT Math Resources
Example Questions
Example Question #2 : How To Find Out If Lines Are Perpendicular
Line , which follows the equation
, intersects line
at
. If line
also passes through
, are
and
perpendicular?
Yes, because the product of their slopes is not .
No, because the product of their slopes is
No, because the product of their slope is not .
Yes, because the product of their slopes is .
Yes, because the product of their slopes is .
The product of perpendicular slopes is always . Knowing this, and seeing that the slope of line
is
, we know any perpendicular line will have a slope of
.
Since line passes through
and
, we can use the slope equation:
Since the two slopes' product is , the lines are perpendicular.
Example Question #3 : How To Find Out If Lines Are Perpendicular
Are the following two lines perpendicular:
and
For two lines to be perpendicular they have to have slopes that multiply to get . The slope is found from the
in the general equation:
.
For the first line, and for the second
.
and so the lines are not perpendicular.
Example Question #2 : How To Find Out If Lines Are Perpendicular
Which of the following equations represents a line that is perpendicular to the line with points and
?
If lines are perpendicular, then their slopes will be negative reciprocals.
First, we need to find the slope of the given line.
Because we know that our given line's slope is , the slope of the line perpendicular to it must be
.
Example Question #711 : Act Math
Consider the lines described by the following two equations:
4y = 3x2
3y = 4x2
Find the vertical distance between the two lines at the points where x = 6.
48
12
36
21
44
21
Since the vertical coordinates of each point are given by y, solve each equation for y and plug in 6 for x, as follows:
Taking the difference of the resulting y -values give the vertical distance between the points (6,27) and (6,48), which is 21.
Example Question #712 : Act Math
For the line
Which one of these coordinates can be found on the line?
(9, 5)
(6, 5)
(6, –12)
(3, 7)
(3, –6)
(3, –6)
To test the coordinates, plug the x-coordinate into the line equation and solve for y.
y = 1/3x -7
Test (3,-6)
y = 1/3(3) – 7 = 1 – 7 = -6 YES!
Test (3,7)
y = 1/3(3) – 7 = 1 – 7 = -6 NO
Test (6,-12)
y = 1/3(6) – 7 = 2 – 7 = -5 NO
Test (6,5)
y = 1/3(6) – 7 = 2 – 7 = -5 NO
Test (9,5)
y = 1/3(9) – 7 = 3 – 7 = -4 NO
Example Question #713 : Act Math
Solve the following system of equations:
–2x + 3y = 10
2x + 5y = 6
(3, 5)
(–2, 2)
(2, 2)
(–2, –2)
(3, –2)
(–2, 2)
Since we have –2x and +2x in the equations, it makes sense to add the equations together to give 8y = 16 yielding y = 2. Then we substitute y = 2 into one of the original equations to get x = –2. So the solution to the system of equations is (–2, 2)
Example Question #714 : Act Math
Which of the following sets of coordinates are on the line ?
when plugged in for
and
make the linear equation true, therefore those coordinates fall on that line.
Because this equation is true, the point must lie on the line. The other given answer choices do not result in true equalities.
Example Question #715 : Act Math
Which of the following points can be found on the line ?
We are looking for an ordered pair that makes the given equation true. To solve, plug in the various answer choices to find the true equality.
Because this equality is true, we can conclude that the point lies on this line. None of the other given answer options will result in a true equality.
Example Question #1 : How To Find Out If A Point Is On A Line With An Equation
Which of the following points is on the line ?
The only thing that is necessary to solve this question is to see if a given value will provide you with the
value paired with it. Among the options provided, only
works. This is verified by the following simple substitution:
Example Question #716 : Act Math
What is the slope of line 3 = 8y - 4x?
-2
0.5
2
-0.5
0.5
Solve equation for y. y=mx+b, where m is the slope
All ACT Math Resources
![Learning Tools by Varsity Tutors](https://vt-vtwa-app-assets.varsitytutors.com/assets/problems/og_image_practice_problems-9cd7cd1b01009043c4576617bc620d0d5f9d58294f59b6d6556fd8365f7440cf.jpg)