1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
igor_vitrenko [27]
3 years ago
5

Solve this quadratic equation by completing the square x^2+6x=18

Mathematics
2 answers:
cestrela7 [59]3 years ago
4 0

Answer:

( x + 3 )² - 27

Step-by-step explanation:

x² + 6x = 18

→ Minus 18 from both sides to get a quadratic equation

x² + 6x - 18

⇒Completed square from is ( x + a )² + b

⇒The value of 'a' will always be half the 'b' value in the equation

ax² + bx + c

→( x + 3 )² + b

Expand out the equation to find 'b'

x² + 6x + 9

We have do something to get from 9 to - 18 which -27

So the answer is ( x + 3 )² -27

Gnoma [55]3 years ago
4 0

Answer:

-8.20 (3sf) , 2.20 (3sf)

Step-by-step explanation:

x2 + 6x = 18

halve the coefficient of x and square it, in this case it is ( 6 / 2 )2 which is 9)

x2 + 6x + 9 - 9 = 18

+ 9 on both sides,

( x + 3 )2 =27

ok now sq. root both sides

x + 3 = ± \sqrt{27\\}

x + 3 = ± 5.196 (4 sf)

x = -8.20 (3 sf) or x = 2.20 (3sf)

You might be interested in
What is the answer to 8-x=3x
Andrew [12]
Move the 8 over
-x=3x-8
Move the 3x over
-x-3x=8
-4x=8
Divide by -4
x=-2
8 0
3 years ago
Read 2 more answers
A gas tank on a car holds 16 gallons of gasoline and can travel 480 miles on a full tank. How many miles can the car travel usin
tamaranim1 [39]

16 gal... 480 mi
1 gal... 480/16 = 30 mi
9 gal.. 30*9 = 270 mi

4 0
1 year ago
Read 2 more answers
There are 450 vehicles in a car lot. Select the correct value for the umber of vehicles of each type that are in the lot. Hybrid
GenaCL600 [577]
Hybrid 126
sport utility 90
sedan 234
5 0
3 years ago
Read 2 more answers
Emily earns $15 for each car she washes. Create an equation to represent the relationship between the number of cars washed, C,
scoundrel [369]

Answer:

An equation is c = 15m

Step-by-step explanation:

5 0
3 years ago
You purchased a smartphone using your Visa® credit card. Your Visa has a monthly finance charge of 2.5% beginning the first of t
polet [3.4K]
Answer is a idk the math teacher is not a teacher or teacher that she is going through so I am going
3 0
3 years ago
Other questions:
  • A hemispherical bowl of radius 12 inches is filled to a depth of h​ inches, where 0less than or equalshless than or equals12. Fi
    7·1 answer
  • Rewrite 1÷4n and 3÷16n using the LCD as the denominator
    10·1 answer
  • Can anyone help with this and explain...thanks so much!​
    10·2 answers
  • How many oz are in a pound
    9·2 answers
  • WILL GIVE BRAINLIEST!!!!!! PLEASE HELP ME!!! 12 POINTS!!!!!
    8·1 answer
  • I enter the mall with 75 dollars. I spend a dollars at American Eagle, which is $4 more than the amount I spent at Banana Republ
    15·1 answer
  • Who likes my profile picture will mark branlist
    11·2 answers
  • The volume Vof a cylindrical can is represented by the formula V=πr2h, where h is the height and r is the radius. A cylindrical
    7·1 answer
  • PLEasE HELPPP WITH THISSSSS IF U KNOW THE ANSWER PLS TELL ME LIKE THIS :
    8·1 answer
  • Tyler's mom purchased a savings bond for Tyler. One year after it was purchased, the value of the savings bond was $156. If the
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!