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Elementary Technical Mathematics

Dale Ewen, C. Robert Nelson

Chapter 11

Quadratic Equations - all with Video Answers

Educators


Chapter Questions

01:54

Problem 1

If $a b=0$, what is known about either $a$ or $b$ ?

Melissa Barry
Melissa Barry
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01:09

Problem 2

Solve for $x: 3 x(x-2)=0$

Sherrie Fenner
Sherrie Fenner
Numerade Educator
00:37

Problem 3

Solve each equation by factoring:
$x^2-4=0$

Amy Jiang
Amy Jiang
Numerade Educator
01:17

Problem 4

Solve each equation by factoring:
$x^2-x=6$

Allison Knapp
Allison Knapp
Numerade Educator
00:24

Problem 5

Solve each equation by factoring:
$5 x^2-6 x=0$

Amy Jiang
Amy Jiang
Numerade Educator
04:05

Problem 6

Solve each equation by factoring:
$x^2-3 x-28=0$

AG
Ankit Gupta
Numerade Educator
00:53

Problem 7

Solve each equation by factoring:
$x^2-14 x=-45$

Jake Zanazzi
Jake Zanazzi
Numerade Educator
03:37

Problem 8

Solve each equation by factoring:
$x^2-18-3 x=0$

AG
Ankit Gupta
Numerade Educator
00:31

Problem 9

Solve each equation by factoring:
$3 x^2+20 x+32=0$

Erika Bustos
Erika Bustos
Numerade Educator
03:01

Problem 10

Solve each equation using the quadratic formula (when necessary, round results to three significant digits):
$3 x^2-16 x-12=0$

Christine Anacker
Christine Anacker
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02:03

Problem 11

Solve each equation using the quadratic formula (when necessary, round results to three significant digits):
$x^2+7 x-5=0$

Cory Kuzinski
Cory Kuzinski
Numerade Educator
02:55

Problem 12

Solve each equation using the quadratic formula (when necessary, round results to three significant digits):
$2 x^2+x=15$

Khanh Ha
Khanh Ha
Numerade Educator
02:00

Problem 13

Solve each equation using the quadratic formula (when necessary, round results to three significant digits):
$x^2-4 x=2$

AG
Ankit Gupta
Numerade Educator
02:06

Problem 14

Solve each equation using the quadratic formula (when necessary, round results to three significant digits):
$3 x^2-4 x=5$

Cory Kuzinski
Cory Kuzinski
Numerade Educator
01:10

Problem 15

The area of a piece of plywood is $36 \mathrm{ft}^2$. Its length is $5 \mathrm{ft}$ more than its width. Find its length and width.

Kristen Karbon
Kristen Karbon
Numerade Educator
01:39

Problem 16

A variable electric current is given by the formula $i=t^2-12 t+36$, where $t$ is in $\mu \mathrm{s}$. At what times is the current $i$ equal to a. $4 \mathrm{~A}$ ? b. $0 \mathrm{~A}$ ? c. $10 \mathrm{~A}$ ?

Kratika Bhadauria
Kratika Bhadauria
Numerade Educator
01:54

Problem 17

Draw the graph of each equation and label each vertex:
$y=x^2-x-6$

Erika Bustos
Erika Bustos
Numerade Educator
00:07

Problem 18

Draw the graph of each equation and label each vertex:
$y=-3 x^2+2$

Katelyn Chen
Katelyn Chen
Numerade Educator
00:24

Problem 19

Express each number in terms of $j$ :
$\sqrt{-36}$

Wendi Zhao
Wendi Zhao
Numerade Educator
00:41

Problem 20

Express each number in terms of $j$ :
$\sqrt{-73}$

Wendi Zhao
Wendi Zhao
Numerade Educator
00:55

Problem 21

Simplify:
$j^{12}$

Sherrie Fenner
Sherrie Fenner
Numerade Educator
00:55

Problem 22

Simplify:
$j^{27}$

Sherrie Fenner
Sherrie Fenner
Numerade Educator
01:06

Problem 23

Determine the nature of the roots of each quadratic equation without solving it:
$9 x^2+30 x+25=0$

Maurizia De Palma
Maurizia De Palma
Numerade Educator
00:58

Problem 24

Determine the nature of the roots of each quadratic equation without solving it:
$3 x^2-2 x+4=0$

Charles Carter
Charles Carter
Numerade Educator
02:25

Problem 25

Solve each equation using the quadratic formula (when necessary, round results to three significant digits):
$x^2-4 x+5=0$

AG
Ankit Gupta
Numerade Educator
00:36

Problem 26

Solve each equation using the quadratic formula (when necessary, round results to three significant digits):
$5 x^2-6 x+4=0$

AG
Ankit Gupta
Numerade Educator
01:30

Problem 27

A solar-heated house has a rectangular heat collector with a length $1 \mathrm{ft}$ more than three times its width. The area of the collector is $21.25 \mathrm{ft}^2$. Find its length and width.

Matt Gibson
Matt Gibson
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Problem 28

A rectangular opening is $15 \mathrm{in}$. wide and $26 \mathrm{in}$. long. (See Illustration 1.) A strip of constant width is to be removed from around the opening to increase the area to $672 \mathrm{in}^2$. How wide must the strip be?

Amelia Hardy
Amelia Hardy
Numerade Educator