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
qaws [65]
3 years ago
10

What are the solutions of the equation x6 + 6x3 + 5 = 0? Use factoring to solve.

Mathematics
1 answer:
lapo4ka [179]3 years ago
6 0

Consider the equation x^6+6x^3+5=0.

First, you can use the substitution t=x^3, then x^6=(x^3)^2=t^2 and equation becomes t^2+6t+5=0. This equation is quadratic, so

D=6^2-4\cdot 5\cdot 1=36-20=16=4^2,\ \sqrt{D}=4,\\ \\ t_{1,2}=\dfrac{-6\pm 4}{2} =-5,-1.

Then you can factor this equation:

(t+5)(t+1)=0.

Use the made substitution again:

(x^3+5)(x^3+1)=0.

You have in each brackets the expression like a^3+b^3 that is equal to (a+b)(a^2-ab+b^2). Thus,

x^3+5=(x+\sqrt[3]{5})(x^2-\sqrt[3]{5}x+\sqrt[3]{25}) ,\\x^3+1=(x+1)(x^2-x+1)

and the equation is

(x+\sqrt[3]{5})(x^2-\sqrt[3]{5}x+\sqrt[3]{25})(x+1)(x^2-x+1)=0.

Here x_1=-\sqrt[3]{5} , x_2=-1 and you can sheck whether quadratic trinomials have real roots:

1. D_1=(-\sqrt[3]{5}) ^2-4\cdot \sqrt[3]{25}=\sqrt[3]{25} -4\sqrt[3]{25} =-3\sqrt[3]{25}.

2. D_2=(-1)^2-4\cdot 1=1-4=-3.

This means that quadratic trinomials don't have real roots.

Answer: x_1=-\sqrt[3]{5} , x_2=-1

If you need complex roots, then

x_{3,4}=\dfrac{\sqrt[3]{5}\pm i\sqrt{3\sqrt[3]{25}}}{2}   ,\\ \\x_{5,6}=\dfrac{1\pm i\sqrt{3}}{2}.

You might be interested in
What kind of decimal is 0.05? How do you know?
solniwko [45]

Answer:

0.05 is a terminating decimal

Step-by-step explanation:

0.05 is a terminating decimal because it has finite digits.

3 0
2 years ago
Read 2 more answers
HHHHHHHHHHHHEEEEEEEEEEEEEELLLLLLLLLLLLLLLPPPPPPPPPPPPPPPPPPPP
Rasek [7]

A came to C, C was supposed to go to A

8 0
3 years ago
Acellus
shtirl [24]

Answer:

(-2, 3)

Step-by-step explanation:

Think of this in the future:

Counter-clockwise rotations:

90-degree --> (x,y) = (-y,x) ex. (3,2) --> (-2,3)

180-degree --> (x,y) = (-x,-y) ex. (3,2) --> (-3, -2)

270 degree --> (x,y) = (y,-x) ex. (3,2) --> (2, -3)

Clockwise rotations:

90-degree --> (x,y) = (y, -x) ex. (3,2) --> (2, -3)

180-degree --> (x,y) = (-x,-y) ex. (3,2) --> (-3,-2)

270-degree --> (x,y) = (-y, x) ex. (3,2) --> (-2,3)

7 0
3 years ago
Read 2 more answers
5/4 miness 5/8what does it equal ​
Ivan
Answer:
5/8
explanation:
5/4(2)=10/8-5/8
4 0
3 years ago
Someone help asap please, thanks!
Sever21 [200]
Graph B is the correct answer
7 0
3 years ago
Other questions:
  • Find the measures of two supplementary angles if their measures are in the given ratio.<br> 3:7
    10·2 answers
  • Speed between 145.155 and 144.809
    15·1 answer
  • What is the formula of surface area of cone and surface area of hemisphere
    12·1 answer
  • Alana only has $56.47 saved for college, Brainstorm possible reasons why she has only managed to save this
    15·2 answers
  • There are 45 new houses being built in a neighborhood. Last month 1/3 of them were sold. This month 2/5 of the remaining houses
    10·1 answer
  • Factoring polynomials
    6·1 answer
  • Find the missing term.
    13·2 answers
  • ILL GIVE BRAINLIEST ASAP!!!PLEASE DONT PUT A LINK!!
    5·2 answers
  • .
    6·2 answers
  • The equation 2x^2+5kx+k=0, where k is a constant has no real roots. Find possible values of k
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!