All ACT Math Resources
Example Questions
Example Question #1 : How To Graph A Two Step Inequality
Solve and graph the following inequality:
To solve the inequality, the first step is to add to both sides:
The second step is to divide both sides by :
To graph the inequality, you draw a straight number line. Fill in the numbers from to infinity. Infinity can be designated by a ray. Be sure to fill in the number , since the equation indicated greater than OR equal to.
The graph should look like:
Example Question #201 : Coordinate Geometry
Points and lie on a circle. Which of the following could be the equation of that circle?
If we plug the points and into each equation, we find that these points work only in the equation . This circle has a radius of and is centered at .
Example Question #1 : Graphing
Which of the following lines is perpendicular to the line ?
The key here is to look for the line whose slope is the negative reciprocal of the original slope.
In this case, is the negative reciprocal of .
Therefore, the equation of the line which is perpendicular to the original equation is:
Example Question #1 : Graphing
Let D be the region on the (x,y) coordinate plane that contains the solutions to the following inequalities:
, where is a positive constant
Which of the following expressions, in terms of , is equivalent to the area of D?
Example Question #2 : How To Graph Inverse Variation
A triangle is made up of the following points:
What are the points of the inverse triangle?
The inverse of a function has all the same points as the original function, except the x values and y values are reversed. The same rule applies to polygons such as triangles.
Example Question #283 : Advanced Geometry
Electrical power can be generated by wind, and the magnitude of power will depend on the wind speed. A wind speed of (in ) will generate a power of . What is the minimum wind speed needed in order to power a device that requires ?
The simplest way to solve this problem is to plug all of the answer choices into the provided equation, and see which one results in a power of .
Alternatively, one could set up the equation,
and factor, use the quadratic equation, or graph this on a calculator to find the root.
If we were to factor we would look for factors of c that when added together give us the value in b when we are in the form,
.
In our case . So we need factors of that when added together give us .
Thus the following factoring would solve this problem.
Then set each binomial equal to zero and solve for v.
Since we can't have a negative power our answer is .
Example Question #284 : Advanced Geometry
Compared to the graph , the graph has been shifted:
units to the right.
units to the left.
units down.
units up.
units down.
units to the left.
The inside the argument has the effect of shifting the graph units to the left. This can be easily seen by graphing both the original and modified functions on a graphing calculator.
Example Question #1 : How To Graph Complex Numbers
The graph of passes through in the standard coordinate plane. What is the value of ?
To answer this question, we need to correctly identify where to plug in our given values and solve for .
Points on a graph are written in coordinate pairs. These pairs show the value first and the value second. So, for this data:
means that is the value and is the value.
We must now plug in our and values into the original equation and solve. Therefore:
We can now begin to solve for by adding up the right side and dividing the entire equation by .
Therefore, the value of is .
Example Question #1 : How To Graph Complex Numbers
Point A represents a complex number. Its position is given by which of the following expressions?
Complex numbers can be represented on the coordinate plane by mapping the real part to the x-axis and the imaginary part to the y-axis. For example, the expression can be represented graphically by the point .
Here, we are given the graph and asked to write the corresponding expression.
not only correctly identifies the x-coordinate with the real part and the y-coordinate with the imaginary part of the complex number, it also includes the necessary .
correctly identifies the x-coordinate with the real part and the y-coordinate with the imaginary part of the complex number, but fails to include the necessary .
misidentifies the y-coordinate with the real part and the x-coordinate with the imaginary part of the complex number.
misidentifies the y-coordinate with the real part and the x-coordinate with the imaginary part of the complex number. It also fails to include the necessary .
Example Question #1 : How To Graph Complex Numbers
Which of the following graphs represents the expression ?
Complex numbers cannot be represented on a coordinate plane.
Complex numbers can be represented on the coordinate plane by mapping the real part to the x-axis and the imaginary part to the y-axis. For example, the expression can be represented graphically by the point .
Here, we are given the complex number and asked to graph it. We will represent the real part, , on the x-axis, and the imaginary part, , on the y-axis. Note that the coefficient of is ; this is what we will graph on the y-axis. The correct coordinates are .