/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q 9.132 Solve the following quadratic in... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Solve the following quadratic inequality algebraically and write the solution in interval notation.

x2-2x-15≤0

Short Answer

Expert verified

The solution, in interval notation, is -3,5.

Step by step solution

01

Step 1. Given Information

The inequality in standard form is x2-2x-15≤0.

Change the inequality sign to an equal sign and then solve the equation.

x2-2x-15=0x2-5x+3x-15=0x-5x+3=0x=5,x=-3

02

Step 2. Test point

Use the critical points -3and 5 to divide the number line into intervals.

The above number line shows the sign of each quadratic expression using test points from each interval.

Take test pointsx=-5,x=0,x=6

03

Step 3. Check sign of inequality

Check the inequality sign for the above test points.

For x=-5,

x2-2x-15=(-5)2-2(-5)-15=25+10-15=20

For x=0,

x2-2x-15=(0)2-2(0)-15=-15

For x=6,

x2-2x-15=(6)2-2(6)-15=36-12-15=9

04

Step 4. Solution of the inequality in interval notation

The inequality is negative in the second interval only.

The expression equals 0 at points -3and 5.

The solution, in interval notation, is -3,5.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Study anywhere. Anytime. Across all devices.