U4HW6: Quadratic Formula & TI-84 Tutorial
Quadratic Functions Day 6 Homework
1. Try to solve the following quadratic equations by factoring, if you cannot factor use the quadratic formula.
(Remember that to find the x-intercepts, one side of the equation needs to be equal to zero!
i) 4𝑥 ! + 4𝑥 = −3
ii) 3𝑥 ! = 5𝑥 + 2
iii) 𝑥 ! + 2𝑥 − 5 = 0
2. Find the discriminant of the following quadratic equations. Then decide whether the function will have
0, 1 or 2 solutions. Note: You do not actually have to find the solutions.
a) 𝑥 ! − 4𝑥 + 6 = 0
b) 5𝑥 ! − 6𝑥 + 1 = 0
c) 𝑥 ! + 10𝑥 = −25
d) 4𝑥 ! − 12𝑥 + 9 = 0
3. Remembering our new rules about the discriminant, answer the following questions.
a. Find the value of k so that 𝑥 ! + 6𝑥 + 𝑘 = 0 has only one solution.
b. Find the value of k so that 𝑥 ! + 𝑘𝑥 + 16 = 0 has only one solution.
4. TI-84 Tutorial: Changing the Window, Finding the x and y intercepts, Finding the minimum and
maximum points.
Click on the link to this YouTube tutorial (https://www.youtube.com/watch?v=xTofCWXtYyU) and
use it to help you answer the questions below.
a. Graph the cubic function 𝑓 𝑥 = 𝑥 ! + 3𝑥 ! − 15 on
your TI-84 calculator and press graph. Follow the
tutorial to help you change the window for a better
view of the function. Sketch your final graph with
the numbers on the domain and range shown below.
b. Find the coordinates (x, y) for each of the local minimum and maximum points, using the tutorial,
then record them here:
Minimum point ( _______ , ________)
Maximum points (_________, ________) and (________, ________)
c. Find the y-intercept and x-intercept using your graphing calculator, use the tutorial to help you,
then record here:
x-intercept ( _______ , ________ )
y-intercept ( _______ , ________ )