Question

What number should be added to the expression x2 + 14x to change it into a perfect square trinomial?



7

14

28

49

Answer 1

what is half of 14?

Answer 2

im guessing 49

Answer 3

ok next

Answer 4

bingo

Answer 5

correcto :)

Answer 6

Solve the following equation by transforming it into a perfect square trinomial.



x^2 – 14x = 15


{–15, 29}


{–1, 15}


{57, 71}

{–22, 36}

Answer 7

don't be daft

Answer 8

b?

Answer 9

or we can do it that way if you like
start with \[x^2-14+49=15+49\] go to \[(x-7)^2=64\]

Answer 10

now there are two numbers whose square is 64, \(8\) and \(-8\) so \[x-7=8\\x=15\] or \[x-7=-8\\
x=-1\]

Answer 11

bingo

Answer 12

hold on im hungry

Answer 13

that be the method of "completing the square" although you could have written \[x^2-14x-15=0\] then factored as \[(x-15)(x+1)=0\] etc

Answer 14

okie im always right

Answer 15

while you are up, get me a slider

Answer 16

im not at taco bell

Answer 17

so? i'm sure there is one close enough

Answer 18

To solve the equation below by completing the square, what is your first step?



3x^2 + 18x = 21


Add 9 to each side of the equation.


Add 81 to each side of the equation.


Multiply both sides of the equation by 1/3


Multiply both sides of the equation by 1/9

Answer 19

20 mins away

Answer 20

i'll wait

Answer 21

you have to have a leading coefficient of 1 to complete the square , so you have to divide all by 3

Answer 22

which, for some inexplicable reason, they have written as "multiply by 1/3"

Answer 23

time for a snack

Answer 24

TIME FOR A SHNACK

Answer 25

xD

Answer 26

ok i back

Answer 27

next question ;p

Answer 28

oh its d

Answer 29

i was in a trance

Answer 30

it's not D

Answer 31

one third, not one ninth

Answer 32

oh sorry i meant one third

Answer 33

its D for me

Answer 34

it's C in the list you posted for us :P

Answer 35

yup

Answer 36

Use the quadratic formula to solve x^2 + 8x + 9 = 0. Estimate irrational solutions to the nearest tenth.



{–3.7, 14.3}


{–6.6, –1.4}


{–18, 10}


{–13.3, –2.7}

Answer 37

http://www.wolframalpha.com/input/?i=x^2+%2B+8x+%2B+9+%3D+0
click on "approximate form"

Answer 38

b

Answer 39

bingo

Answer 40

Nick is solving the equation 3x^2 = 20 – 7x with the quadratic formula.



What values should he use for a, b, and c?




a = 3
b = 20

c = –7


a = 3
b = –7

c = 20


a = 3
b = 7

c = –20


a = 3
b = –20

c = 7

Answer 41

c?

Answer 42

a trick question

Answer 43

ok that was wrong !

Answer 44

3x^2 = 20 – 7x

3x^2 + 7x - 20 = 0

a = 3
b = 7
c = -20

Answer 45

\[3x^2+7x-20=0\]is the first step

Answer 46

so yeah, C

Answer 47

and that's in the form of \(ax^2 +bx + c\)

Answer 48

really

Answer 49

yes

Answer 50

i know it was a totally lucky guess

Answer 51

yes it was

Answer 52

ok next

Answer 53

Calculate the discriminant.


x^2 + 2x – 2 = 0



–8

–4

8

12

Answer 54

b?

Answer 55

discriminant = b^2 - 4ac

2^2 - 4(1)(2)
4 - 8
-4

Answer 56

so correct

Answer 57

damn ! another lucky guess or did you do it?

Answer 58

i did it

Answer 59

What number would you have to add to both sides to complete the square?


x^2 – 16x = –8



–16

–64

16

64

Answer 60

c?

Answer 61

no

Answer 62

half of 16 is ?

Answer 63

half of 16?

Answer 64

8

Answer 65

and then square that ;p

Answer 66

d

Answer 67

and then square that ;p

Answer 68

wow nice

Answer 69

yeah D

Answer 70

yeah D

Answer 71

Solve by using the perfect squares method.



x^2 + 12x + 36 = 0



–18


18

6

–6

Answer 72

-6?

Answer 73

yes

Answer 74

\[(x+6)^2=0\\
x+6=0\\
x=-6\]

Answer 75

(x+6)^2 = 0
x = -6

Answer 76

Lijuan is solving the equation x^2 – x = 14 with the quadratic formula. What values should she use for a, b, and c?



a = –1, b = 1, c = 14

a = 1, b = –1, c = 14

a = –1, b = 1, c = –14


a = 1, b = –1, c = –14

Answer 77

got another lucky guess?

Answer 78

hahahahahhahahahaha no

Answer 79

oh

Answer 80

x^2 – x = 14

x^2 - x - 14 = 0
ax^2 - bx - c = 0

what is a, b, and c?

Answer 81

\[x^2-x-14=0\] how about now?

Answer 82

c?

Answer 83

no, a is not minus one

Answer 84

d

Answer 85

yes

Answer 86

Use the discriminant to determine the number and type of solutions the equation has.


x^2 + 6x + 12 = 0



two irrational solutions

no real solution

one real solution

two rational solutions

Answer 87

b^2 - 4ac

6^2 - 4(1)(12)

simplify it more

Answer 88

wonder why they ask to do this by the discriminant always

Answer 89

a?

Answer 90

\[x^2 + 6x + 12 = 0 \\
x^2+6x=-12\\
(x+3)^2=-12+9=-3\] nope a square can't be negative

Answer 91

bingo, it's a

Answer 92

no it aint

Answer 93

\[36-48=-12\] is negative
no real solution

Answer 94

my bad, got confused with imaginary and irrational

Answer 95

this should be my pfp

Answer 96

yeah you'd get lots of help then...