Intermediate Algebra: Connecting Concepts through Application

Published by Brooks Cole
ISBN 10: 0-53449-636-9
ISBN 13: 978-0-53449-636-4

Chapter 4 - Quadratic Functions - 4.4 Solving Quadratic Equations by the Square Root Property and Completing the Square - 4.4 Exercises - Page 349: 73

Answer

See graph

Work Step by Step

The function that we want to graph is shown below. Follow the steps outline to graph the function.$$ \begin{aligned} h(x)=(x+2)^2-5. \end{aligned} $$ Step 1: We first determine the direction in which the function opens: The given function opens upward because the constant, $a= 1$ is positive. Step 2:Determine the vertex and the equation for the axis of symmetry. The vertex is $(-2,-5)$ and the equation for the axis of symmetry is $x = -2$ Step 3: Find the $y$ and $x$-intercepts. To find the $y$-intercept, set $x= 0$ to find the value of $y$. Similarly, to find the $x$ intercept, set $ y= 0$ to find the values of $x$. $$ \begin{aligned} h(0)& =(0+2)^2-5= -1\\ &\textbf{y-intercept: (0,-1)}. \end{aligned} $$ Set $ y = 0$ and solve. $$ \begin{aligned} (x+2)^2-5& =0\\ (x+2)^2&= 5 \\ x+2& =\pm\sqrt{5}\\ x&= -2\pm \sqrt{5}. \end{aligned} $$ Find the two separate solutions: $$ \begin{aligned} x&=-2+\sqrt{5}\approx = 0.24 \\ \textbf{or}\\ x&= -2-\sqrt{5}\approx = -4.24. \end{aligned} $$ $x$-intercepts: $(-4.24,0), (0.24 , 0)$. Step 4: Find the domain and range of the function and sketch it. Domain: All real numbers, Range: $[-5, \infty) $.
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