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
r-ruslan [8.4K]
2 years ago
14

X^3+7x^2-36x 3 +7x 2 −36x, cubed, plus, 7, x, squared, minus, 36 The polynomial above has zeros at -6−6minus, 6 and 222. If the

remaining zero is zzz, then what is the value of -z−zminus, z?

Mathematics
1 answer:
Dominik [7]2 years ago
4 0

Answer:

Step-by-step explanation:

Equation:

x^3 + 7x^2 - 36

Given that:

x1 = -6

x2 = 2

x3 = z

Let the zeros be,

x + 6, x - 2

Multiplying both of these factors ,

(x + 6) × (x - 2)

x^2 + 6x - 2x - 12

= x^2 + 4x - 12

Dividing the polynomial, x^3 + 7x^2 - 36 with the above quadratic equation,

We get:

x^3 + 7x^2 - 36 ÷ x^2 + 4x - 12

= x + 3

z; x + 3 = 0

x = -3

z = -3

-z = 3

You might be interested in
1. Write the following degrees in radian measure
ale4655 [162]
I’m on the same question sis ♥️
5 0
3 years ago
W/4 = -11 <br> please help !!!
Elis [28]
-44 because if u multiply -11 by 4 you get -44 and when divided by 4 you get -11
3 0
3 years ago
Alberta has 5 shirts and 4 pants. 3 of the shirts are her favorite and 2 of the pants are her favorite. If Alberta chooses an ou
tiny-mole [99]

Answer:

\frac{3}{10}

Step-by-step explanation:

In probability, "AND" means "multiplication" and

"OR" means "addition".

We want the probability that she picks FAVORITE SHIRT "AND" FAVORITE PANT.

Probability that she picks favorite shirt = 3/5

Probability that she picks favorite pants = 2/4 = 1/2

Since, "AND", we "multiply" both to get:

3/5 * 1/2 = 3/10

5 0
3 years ago
Prove that
Pani-rosa [81]
Let's start from what we know.

(1)\qquad\sum\limits_{k=1}^n1=\underbrace{1+1+\ldots+1}_{n}=n\cdot 1=n\\\\\\&#10;(2)\qquad\sum\limits_{k=1}^nk=1+2+3+\ldots+n=\dfrac{n(n+1)}{2}\quad\text{(arithmetic  series)}\\\\\\&#10;(3)\qquad\sum\limits_{k=1}^nk\ \textgreater \ 0\quad\implies\quad\left|\sum\limits_{k=1}^nk\right|=\sum\limits_{k=1}^nk

Note that:

\sum\limits_{k=1}^n(-1)^k\cdot k^2=(-1)^1\cdot1^2+(-1)^2\cdot2^2+(-1)^3\cdot3^2+\dots+(-1)^n\cdot n^2=\\\\\\=-1^2+2^2-3^2+4^2-5^2+\dots\pm n^2

(sign of last term will be + when n is even and - when n is odd).
Sum is finite so we can split it into two sums, first S_n^+ with only positive trems (squares of even numbers) and second S_n^- with negative (squares of odd numbers). So:

\sum\limits_{k=1}^n(-1)^k\cdot k^2=S_n^+-S_n^-

And now the proof.

1) n is even.

In this case, both S_n^+ and S_n^- have \dfrac{n}{2} terms. For example if n=8 then:

S_8^+=\underbrace{2^2+4^2+6^2+8^2}_{\frac{8}{2}=4}\qquad\text{(even numbers)}\\\\\\&#10;S_8^-=\underbrace{1^2+3^2+5^2+7^2}_{\frac{8}{2}=4}\qquad\text{(odd numbers)}\\\\\\

Generally, there will be:

S_n^+=\sum\limits_{k=1}^\frac{n}{2}(2k)^2\\\\\\S_n^-=\sum\limits_{k=1}^\frac{n}{2}(2k-1)^2\\\\\\

Now, calculate our sum:

\left|\sum\limits_{k=1}^n(-1)^k\cdot k^2\right|=\left|S_n^+-S_n^-\right|=&#10;\left|\sum\limits_{k=1}^\frac{n}{2}(2k)^2-\sum\limits_{k=1}^\frac{n}{2}(2k-1)^2\right|=\\\\\\=&#10;\left|\sum\limits_{k=1}^\frac{n}{2}4k^2-\sum\limits_{k=1}^\frac{n}{2}\left(4k^2-4k+1\right)\right|=\\\\\\

=\left|4\sum\limits_{k=1}^\frac{n}{2}k^2-4\sum\limits_{k=1}^\frac{n}{2}k^2+4\sum\limits_{k=1}^\frac{n}{2}k-\sum\limits_{k=1}^\frac{n}{2}1\right|=\left|4\sum\limits_{k=1}^\frac{n}{2}k-\sum\limits_{k=1}^\frac{n}{2}1\right|\stackrel{(1),(2)}{=}\\\\\\=&#10;\left|4\dfrac{\frac{n}{2}(\frac{n}{2}+1)}{2}-\dfrac{n}{2}\right|=\left|2\cdot\dfrac{n}{2}\left(\dfrac{n}{2}+1\right)-\dfrac{n}{2}\right|=\left|n\left(\dfrac{n}{2}+1\right)-\dfrac{n}{2}\right|=\\\\\\&#10;

=\left|\dfrac{n^2}{2}+n-\dfrac{n}{2}\right|=\left|\dfrac{n^2}{2}+\dfrac{n}{2}\right|=\left|\dfrac{n^2+n}{2}\right|=\left|\dfrac{n(n+1)}{2}\right|\stackrel{(2)}{=}\\\\\\\stackrel{(2)}{=}&#10;\left|\sum\limits_{k=1}^nk\right|\stackrel{(3)}{=}\sum\limits_{k=1}^nk

So in this case we prove, that:

 \left|\sum\limits_{k=1}^n(-1)^k\cdot k^2\right|=\sum\limits_{k=1}^nk

2) n is odd.

Here, S_n^- has more terms than S_n^+. For example if n=7 then:

S_7^-=\underbrace{1^2+3^2+5^2+7^2}_{\frac{n+1}{2}=\frac{7+1}{2}=4}\\\\\\&#10;S_7^+=\underbrace{2^2+4^4+6^2}_{\frac{n+1}{2}-1=\frac{7+1}{2}-1=3}\\\\\\

So there is \dfrac{n+1}{2} terms in S_n^-, \dfrac{n+1}{2}-1 terms in S_n^+ and:

S_n^+=\sum\limits_{k=1}^{\frac{n+1}{2}-1}(2k)^2\\\\\\&#10;S_n^-=\sum\limits_{k=1}^{\frac{n+1}{2}}(2k-1)^2

Now, we can calculate our sum:

\left|\sum\limits_{k=1}^n(-1)^k\cdot k^2\right|=\left|S_n^+-S_n^-\right|=&#10;\left|\sum\limits_{k=1}^{\frac{n+1}{2}-1}(2k)^2-\sum\limits_{k=1}^{\frac{n+1}{2}}(2k-1)^2\right|=\\\\\\=&#10;\left|\sum\limits_{k=1}^{\frac{n+1}{2}-1}4k^2-\sum\limits_{k=1}^{\frac{n+1}{2}}\left(4k^2-4k+1\right)\right|=\\\\\\=&#10;\left|\sum\limits_{k=1}^{\frac{n-1}{2}-1}4k^2-\sum\limits_{k=1}^{\frac{n+1}{2}}4k^2+\sum\limits_{k=1}^{\frac{n+1}{2}}4k-\sum\limits_{k=1}^{\frac{n+1}{2}}1\right|=\\\\\\

=\left|\sum\limits_{k=1}^{\frac{n-1}{2}-1}4k^2-\sum\limits_{k=1}^{\frac{n+1}{2}-1}4k^2-4\left(\dfrac{n+1}{2}\right)^2+\sum\limits_{k=1}^{\frac{n+1}{2}}4k-\sum\limits_{k=1}^{\frac{n+1}{2}}1\right|=\\\\\\=&#10;\left|-4\left(\dfrac{n+1}{2}\right)^2+4\sum\limits_{k=1}^{\frac{n+1}{2}}k-\sum\limits_{k=1}^{\frac{n+1}{2}}1\right|\stackrel{(1),(2)}{=}\\\\\\&#10;\stackrel{(1),(2)}{=}\left|-4\dfrac{n^2+2n+1}{4}+4\dfrac{\frac{n+1}{2}\left(\frac{n+1}{2}+1\right)}{2}-\dfrac{n+1}{2}\right|=\\\\\\

=\left|-n^2-2n-1+2\cdot\dfrac{n+1}{2}\left(\dfrac{n+1}{2}+1\right)-\dfrac{n+1}{2}\right|=\\\\\\=&#10;\left|-n^2-2n-1+(n+1)\left(\dfrac{n+1}{2}+1\right)-\dfrac{n+1}{2}\right|=\\\\\\=&#10;\left|-n^2-2n-1+\dfrac{(n+1)^2}{2}+n+1-\dfrac{n+1}{2}\right|=\\\\\\=&#10;\left|-n^2-n+\dfrac{n^2+2n+1}{2}-\dfrac{n+1}{2}\right|=\\\\\\=&#10;\left|-n^2-n+\dfrac{n^2}{2}+n+\dfrac{1}{2}-\dfrac{n}{2}-\dfrac{1}{2}\right|=\left|-\dfrac{n^2}{2}-\dfrac{n}{2}\right|=\left|-\dfrac{n^2+n}{2}\right|=\\\\\\

=\left|-\dfrac{n(n+1)}{2}\right|=|-1|\cdot\left|\dfrac{n(n+1)}{2}\right|=\left|\dfrac{n(n+1)}{2}\right|\stackrel{(2)}{=}\left|\sum\limits_{k=1}^nk\right|\stackrel{(3)}{=}\sum\limits_{k=1}^nk

We consider all possible n so we prove that:

\forall_{n\in\mathbb{N}}\quad\left|\sum\limits_{k=1}^n(-1)^k\cdot k^2\right|=\sum\limits_{k=1}^nk
7 0
3 years ago
Mathew mowed lawns for 3 hours and earned $6.20 per hour. Then he washed windows for 4 hours and earned $6.90 per hour. What wer
Shtirlitz [24]

Answer:

$6.60

Step-by-step explanation:

6.20 x 3 = 18.60

6.90 x 4 = 27.60

18.60 + 27.60 = 46.20

46.20 ÷ 7 = 6.60

6 0
3 years ago
Other questions:
  • What is the value of the expression (-8/9) + (-2/3) x (-4 1/2)
    14·1 answer
  • Solve 3x+2y=4 4x+3y=7 algebraically
    11·1 answer
  • Find 114/40 give the answer as a decimal with 2 digit after the decimal point
    10·1 answer
  • Write two inequalities that would have the solution set as graphed below.
    7·1 answer
  • Correct first step to solving 9 (x + 2)=90
    7·2 answers
  • 8^-3 x 8^-2 x 8^5 <br>a. 8^30<br>b. 1<br>c. 80<br>d. 24
    15·1 answer
  • A $100 pair of headphones is marked down by 10% and you also have a 20% off coupon. What is the final price, before tax?
    15·1 answer
  • Can anyone help? It’s not 14, I’ll give Brainly + 15 pts
    7·1 answer
  • PLEASE HELP ASAPPPPP
    11·1 answer
  • How do outliers affect the mean of a data set?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!