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
Darya [45]
3 years ago
8

X^2=4x-15 solve with Quadratic formula

Mathematics
1 answer:
bulgar [2K]3 years ago
7 0

Answer:

x=2+i\sqrt{11}

x=2-i\sqrt{11}

Step-by-step explanation:

we have

x^{2} =4x-15 -------> x^{2}-4x+15=0

we know that

The formula to solve a quadratic equation of the form ax^{2} +bx+c=0 is equal to

x=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}

in this problem we have

x^{2}-4x+15=0

so

a=1\\b=-4\\c=15

substitute in the formula

x=\frac{-(-4)(+/-)\sqrt{-4^{2}-4(1)(15)}} {2(1)}

x=\frac{4(+/-)\sqrt{16-60}} {2}

Remember that

i=\sqrt{-1}

x=\frac{4(+/-)\sqrt{-44}} {2}

x=\frac{4(+/-)2i\sqrt{11}} {2}

x=\frac{4(+)2i\sqrt{11}}{2}=2+i\sqrt{11}

x=\frac{4(-)2i\sqrt{11}}{2}=2-i\sqrt{11}

You might be interested in
Please help me with the following questions. Thanks in advance!!
Orlov [11]

Answer:

Step-by-step explanation:

Eight

590 = 1800 e^(-0.4t)     Divide by 1800

0.32778 = e^(-0.4t)       Put the value for e in the denominator.

0.32778 = 1 / e^(0.4t)   Notice the sign's gone. Multiply both sides by e^(0.4t)

0.32778 *e^(0.4t) = 1    Divide by 0.32778

e^(0.4t) = 3.0508          Take the natural log of both sides.

0.4t = 1.11542                 Divide both sides by 0.4

t = 2.78855

You should put this in the original equation to see if it checks. It does.

=============================

Nine

3^(3 - 3x) + 6 = 42         Subtract 6 from both sides

3^(3 - 3x) = 36               Take the log of both sides.

(3 - 3x) ln(3) = ln 36

(3 - 3x) *1.098612 = 3.58352   Divide by 1.098612

3 - 3x = 3.26186             Subtract 3 from both sides

- 3x = 0.26186                 Divide by - 3

x = - 0.087287    

4 0
3 years ago
Which equation can be simplified to find the inverse of y = 2x²?
siniylev [52]

Answer:

y=1/2x²

Step-by-step explanation:

y=2x-²

y=1/2x²

8 0
3 years ago
A composite figure is made up of
son4ous [18]
a composit figure is made up of two figures
6 0
2 years ago
Read 2 more answers
the runner's time to complete the marathon is 45 minutes. The time to complete the last marathon was 49.5 minutes. What is the p
Lana71 [14]

Answer:

9.09%

Step-by-step explanation:

To find percent decrease you have to use this equation:

Percent Decrease = \frac{Initial -New}{Initial} x 100

Initial = 49.5

New = 45

Plug in and solve:

PD = \frac{49.5-45}{49.5} x 100\\\\PD = \frac{4.5}{49.5} x 100 \\\\PD = 0.0909 x 100\\\\PD = 9.09

The percent decrease is 9.09%

<em>Hope this helps!!</em>

<em>- Kay :)</em>

6 0
3 years ago
A lacrosse player throws a ball in the air from an initial height of 7 feet. The ball has an initial vertical velocity of 90 fee
aleksklad [387]
I think your suppose to divide 90 and 3
5 0
3 years ago
Other questions:
  • A={2 3 4 5} and B= {6 7 8 9}, what is A B
    6·2 answers
  • How do I put 3(x+7) in distributive property
    11·1 answer
  • What would be an appropriate measure to describe the diameter of a music record?
    14·2 answers
  • The points in the table have been graphed in the scatter plot below. What is the best equation for the trend line, and the value
    10·1 answer
  • What number is 20% of 700​
    13·2 answers
  • Given f(x) = -x – 5, solve for a when f(x) = 4.
    9·1 answer
  • It is given that in △ABC, AD ⊥ BC. Using the definition of sine with angle C in △ACD results in sin(C) = . Using the multiplicat
    13·2 answers
  • PLEASEEEEEE HELP ME !!!!
    8·2 answers
  • Use substitution to solve this problem <br>m = -2, n = 4, p = 3, q = -8<br>2q - p =?​
    13·1 answer
  • You have been assigned to determine whether more people prefer Coke or Pepsi. Assume that roughly half the population prefers Co
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!