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
Anna71 [15]
2 years ago
10

Solve the equation by completing the square x^2-3x-18=0

Mathematics
1 answer:
Alexandra [31]2 years ago
4 0

Answer:

x = -3, 6

Step-by-step explanation:

First, add 18 to both sides

x² - 3x - 18 = 0

           + 18    + 18

x² - 3x = 18

Add 9/4 to both sides because that is the square of half of -3

x² - 3x + 9/4 = 18 + 9/4

Multiply both sides by 4 to get rid of the fractions

(x² - 3x + 9/4 = 18 + 9/4)4

4x² - 12x + 9 = 72 + 9 = 81

Factor the left side of the equation

(2x - 3)² = 81

√(2x - 3)² = √81

Because of the square root, this will result in a positive number and a negative number

2x - 3 = 9

2x - 3 = -9

For both equations, add 3 to both sides then divide by 2

2x - 3 = 9

     + 3   +3

2x = 12

2x/2 = 12/2

x = 6

2x - 3 = -9

    + 3   + 3

2x = -6

x = -3

You might be interested in
What are all the powers of 4 in the range 4 through 1,000​
Pachacha [2.7K]

Answer:

Powers are : 4, 16 64 and 256

and this question type of question was answered from another brainly user as well lol

5 0
3 years ago
Which number is equivalent to 4.8 x 10^4in standard form
MA_775_DIABLO [31]

Answer:

-5b

Step-by-step explanation:

6 0
3 years ago
The temperature falls from 0 degrees to -12.4 degrees in
vova2212 [387]

Answer:

Step-by-step explanation:

The temperature falls from 0 degrees to -12.4

0-(-12.4) = 12.4

12.4/13.4 degree per hours

0.9185 degrees/ hour

4 0
3 years ago
Please explain how you came to your answer, need help ASAP. Will give brainliest
shusha [124]
The vertex is the high point of the curve, (2, 1). The vertex form of the equation for a parabola is
.. y = a*(x -h)^2 +k . . . . . . . for vertex = (h, k)

Using the vertex coordinates we read from the graph, the equation is
.. y = a*(x -2)^2 +1

We need to find the value of "a". We can do that by using any (x, y) value that we know (other than the vertex), for example (1, 0).
.. 0 = a*(1 -2)^2 +1
.. 0 = a*1 +1
.. -1 = a

Now we know the equation is
.. y = -(x -2)^2 +1

_____
If we like, we can expand it to
.. y = -(x^2 -4x +4) +1
.. y = -x^2 +4x -3

=========
An alternative approach would be to make use of the zeros. You can read the x-intercepts from the graph as x=1 and x=3. Then you can write the equation as
.. y = a*(x -1)*(x -3)
Once again, you need to find the value of "a" using some other point on the graph. The vertex (x, y) = (2, 1) is one such point. Subsituting those values, we get
.. 1 = a*(2 -1)*(2 -3) = a*1*-1 = -a
.. -1 = a
Then the equation of the graph can be written as
.. y = -(x -1)(x -3)
In expanded form, this is
.. y = -(x^2 -4x +3)
.. y = -x^2 +4x -3 . . . . . . same as above
5 0
4 years ago
Find the TWO integers whos product is 36 and whose sum is -12
Murljashka [212]
-6, -6 is the answer
5 0
3 years ago
Read 2 more answers
Other questions:
  • How do you write 0.368 in word form
    10·2 answers
  • Draw two possible rectangles for 20 units perimeter find the area
    6·1 answer
  • Hepl im desperate beacuse othis
    12·1 answer
  • use distributive property to simplify the expression 3 (8x + 2y) I need help with my algebra homework someone please help.
    6·1 answer
  • Geneva rode her bike a total of 2 1/2 miles from her house to school first she rode for fits mile from her house to the park the
    12·1 answer
  • (5 + 4 – 2) × (–2) = ?
    7·1 answer
  • Formula of LSA of cuboid , cube and cylinder​
    7·1 answer
  • I need this one, please
    12·1 answer
  • Solve for y <br> 6x - 2y = 12<br> A. y= -3x + 6<br> B. y= 3x - 6<br> C. -3x + 6<br> D. -3x - 6
    8·2 answers
  • Find the fourth degree polynomial function with zeros 6,-6,6i
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!