All Algebra II Resources
Example Questions
Example Question #511 : Intermediate Single Variable Algebra
Find the roots of the quadratic function,
Where is any real number constant not equal to zero.
To find the roots set the function to zero:
,
(1)
Apply the quadratic formula:
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Reminder
Recall that for a quadratic the general formula for the solution in terms of the constant coefficients is given by:
(2)
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Use equation (2) to write a solution for equation (1).
If we simplify the right-hand term in the numerator we obtain:
So now we have for ,
After all the cancellations in the expression above we obtain:
Therefore, the solution set for this equation is:
Example Question #191 : Solving Quadratic Equations
Find the roots of the quadratic function,
The roots are the values of for which:
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Reminder
Recall that for a quadratic the general formula for the solution in terms of the constant coefficients is given by:
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Use the quadratic formula to find the roots.
Notice that is not a real number, and therefore the roots will be complex numbers.
Using the definition of the imaginary unit we can rewrite as follows,
Now we can write the solutions to this problem in the form:
Example Question #191 : Solving Quadratic Equations
Find the roots using the quadratic formula.
For this problem
a=1, coefficient of x^2 term
b=9, the coefficient of the x term
c=15, the constant term
solving the expression shows the roots of -6.79 and -2.21
Example Question #195 : Solving Quadratic Equations
Use the quadratic formula to solve for . Use a calculator to estimate the value to the closest hundredth.
and
and
No solution
and
and
and
Recall that the quadratic formula is defined as:
For this question, the variables are as follows:
Substituting these values into the equation, you get:
Use a calculator to determine the final values.
Example Question #1 : Quadratic Inequalities
Solve the following quadratic inequality, and report your answer in interval form:
The problem is already in standard form, so all we have to at first do is set the quadratic expression = 0 and factor as normal.
Negative x^2's are hard to work with, so we multiply through by -1.
Now we can factor easily.
By the zero product property, each of these factors will be equal to 0.
Since -9 and 1 are our zeros, we just have to test one point in the region between them to find out which region our answer set goes in. Let's test x = 0 in the original inequality.
Since this statement is false, the region between -9 and 1 is not correct. So it must be the region on either side of those points. Since the original inequality was less than or equal to, the boundary points are included. So all values from -infinity to -9 inclusive, and from 1 inclusive to infinity, are solutions. In interval notation we write this as:
Example Question #2 : Quadratic Inequalities
Solve the following quadratic inequality:
First we want to rewrite the quadratic in standard form:
Now we want to set it = 0 and factor and solve like normal.
Using the zero product property, both factors produce a zero:
So the two zeros are -2 and 3, and will mark the boundaries of our answer interval. To find out if the interval is between -2 and 3, or on either side, we simply take a test point between -2 and 3 (for instance, x = 0) and evaluate the original inequality.
Since the above is a true statement, we know that the solution interval is between -2 and 3, the same region where we picked our test point. Since the original inequality was less than or equal, we include the endpoints.
Ergo, .
Example Question #3 : Quadratic Inequalities
What is the discriminant of the following quadratic equation:
The discriminant of a quadratic equation in form is equal to . The given equation is not in that form however, so we must first multiply it out to get it into that form. We therefore obtain:
We therefore have , , and . Our discriminant is therefore:
The correct answer is therefore
Example Question #1 : Quadratic Inequalities
Solve the following quadratic inequality:
and
1. Rewrite the equation in standard form.
2. Set the equation equal to and solve by factoring.
So, and are our zeroes.
3. Test a point between your zeroes to find out if the solution interval is between them or on either side of them. (Try testing by plugging it into your original inequality.)
Because the above statement is true, the solution is the interval between and .
Example Question #4 : Quadratic Inequalities
Solve this inequality.
Combine like terms first.
Factor
The zeroes are 3 and 8 so a number line can be divided into 3 sections.
X<3 works, 3<x<8 does not work, and x>8 works
Example Question #2 : Quadratic Inequalities
Solve:
Start by setting the inequality to zero and by solving for .
Now, plot these two points on to a number line.
Notice that these two numbers effectively divide up the number line into three regions:
, , and
Now, choose a number in each of these regions and put it back in the factored inequality to see which cases are true.
For , let
Since this is not less than , the solution to this inequality cannot lie in this region.
For , let .
Since this will make the inequality true, the solution can lie in this region.
Finally, for , let
Since this number is not less than zero, the solution cannot lie in this region.
Thus, the solution to this inequality is