All Algebra II Resources
Example Questions
Example Question #14 : Transformations Of Parabolic Functions
Write the equation for the parabola shifted 3 units to the right and then reflected across the -axis.
To solve this problem, we could complete the square and shift the equation that way, but the vertex ends up being so this may not be an ideal method. Instead, we know we're shifting the equation 3 units to the right, so we can just plug in for every appearance of x:
To simplify, first expand
Now we can plug that in and continue simplifying:
distribute the 2; combine -3 and -5
combine like terms -12x and x; 18 and -8
Now we want to flip this over the x-axis, meaning that the y coordinates change sign.
This means we have to multiply everything by -1, or simply change the sign of every term on the right side:
Example Question #41 : Parabolic Functions
Describe the translation in
from the parent function
.
Up three units, left one unit
Up three units, right one unit
Down three units, right one unit
Down three units, left one unit
Down three units, right one unit
Below is the standard equation for parabolas;
Therefore,
and
thus,
the translation from the parent function is down three units, right one unit.
Example Question #14 : Transformations Of Parabolic Functions
Given the parabola , what is the new equation if the parabola is shifted left two units, and up four units?
Shifting up and down will result in a change in the y-intercept.
Add four to the equation.
Shifting the parabola to the left two units will change the inner term to , which will be .
Replace the quantity with .
The new equation is:
Example Question #15 : Transformations Of Parabolic Functions
Shift to the left two units and up two units. What is the new equation?
Vertical shifts will change the value of the y-intercept. Since this function is to be shifted up two units, add two to the right side of the equation.
This graph shifted two units to the left indicates that its zeros will also shift to the left two units, which means that the term will become .
Rewrite the equation and expand the binomials.
The new equation is:
Example Question #16 : Transformations Of Parabolic Functions
Shift the parabola three units to the right. What is the new equation?
Shifting this graph three units to the right means that the x-variable will need to be replaced with . Rewrite the equation.
Use the FOIL method to simplify the binomial.
Simplify the right side.
The equation becomes:
The answer is:
Example Question #42 : Parabolic Functions
3 spaces right
3 spaces up
3 spaces down
3 spaces left
3 spaces right
Example Question #43 : Parabolic Functions
Which of the below quadratic functions will be the widest?
To determine how "wide" or "skinny" a parabola is, we look at the leading coefficient.
The smaller the fraction, the wider a parabola will be.
The larger the whole number, the skinnier the parabola will be.
This will give us the widest parabola.
Example Question #44 : Parabolic Functions
Shift up one unit. What is the new equation?
Simplify the following equation by using the FOIL method with the binomial.
Simplify all terms in the parentheses.
Replace the term and simplify.
The equation in standard form is:
Since this parabola is shifted up one unit, add one to the y-intercept.
The answer is:
Example Question #45 : Quadratic Functions
Write the equation for the parabola after it has been reflected over the y-axis, then shifted up 2 and left 4.
First, reflect the equation over the y-axis by switching the sign of x:
Now shift up 2 by adding 2:
Now shift left 4 by adding 4 to x:
first expand
Now multiply
Now plug those back in:
combine like terms
Example Question #3 : Quadratic Functions
Find the -intercepts for the circle given by the equation:
To find the -intercepts (where the graph crosses the -axis), we must set . This gives us the equation:
Because the left side of the equation is squared, it will always give us a positive answer. Thus if we want to take the root of both sides, we must account for this by setting up two scenarios, one where the value inside of the parentheses is positive and one where it is negative. This gives us the equations:
and
We can then solve these two equations to obtain .