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
seropon [69]
3 years ago
10

If 3 times a number minus 2 equals 13, what is the number? A. –6 B. 5 C. 2 D. 4

Mathematics
2 answers:
OverLord2011 [107]3 years ago
8 0
3x - 2 = 13

Add 2 on both sides

3x - 2 + 2 = 13 + 2
3x = 13 + 2
3x = 15

Divide both sides by 3.

3x/3 = 15/3

x = 15/3

x = 5

Your final answer is A. 5<span>.</span>
rosijanka [135]3 years ago
4 0
It is very important to read and understand the words of the problem before getting down to solving the given question. Numerous information's of immense importance are already given in the question. Those information's will come in handy while solving the question.
Let us assume the unknown number to be = x
Then
3x - 2 = 13
3x = 13 + 2
3x = 15
Dividing both sides of the equation by 3, we get
(3/3) *  x = 15/3
1 * x = 5
x = 5
So the unknown number is 5. I hope the procedure is not very tough for you to understand.
You might be interested in
If y = x/k where k is a constant, and y = 5 when x = 30, what is the value of y when x = 60?
Alex777 [14]

Answer:

\huge\boxed{\sf y = 10}

Step-by-step explanation:

<u>Given Equation is:</u>

y = x / k

We know that y = 5 when x = 30

Put it in the above equation

5 = 30 / k

k = 30 / 5

k = 6

<u>Now,</u>

y = ? when x = 60

Put it in the above equation

y = x / k

y = 60 / 6

y = 10

\rule[225]{225}{2}

Hope this helped!

<h3>~AH1807</h3>
7 0
3 years ago
(4) use the method of lagrange multipliers to determine the maximum value of f(x, y) = x a y b (the a and b are two fixed positi
wlad13 [49]
Assuming f(x,y)=x^ay^b. We have Lagrangian

L(x,y,\lambda)=x^ay^b+\lambda(x+y-1)

with partial derivatives (set to 0)[/tex]

L_x=ax^{a-1}y^b+\lambda=0\implies ax^{a-1}y^b=-\lambda
L_y=bx^ay^{b-1}+\lambda=0\implies bx^ay^{b-1}=-\lambda
L_\lambda=x+y-1=0

\implies ax^{a-1}y^b=bx^ay^{b-1}\implies -bx+ay=0
x+y-1=0\implies x+y=1

Solving this system of linear equations yields x=\dfrac a{a+b} and y=\dfrac b{a+b} as the sole critical point, which in turn gives a maximum value of f\left(\dfrac a{a+b},\dfrac b{a+b}\right)=\dfrac{a^ab^b}{(a+b)^{a+b}}.
8 0
3 years ago
Find the measure of
hammer [34]

Answer:

180-43=137....................

7 0
3 years ago
If
Helen [10]

Step-by-step explanation:

3x²+3xy+y²

3×5²+3×5×4+4²

3×25+60+16

75+60+16

151

hope it help u

5 0
3 years ago
Read 2 more answers
Compute the sum:
Nady [450]
You could use perturbation method to calculate this sum. Let's start from:

S_n=\sum\limits_{k=0}^nk!\\\\\\\(1)\qquad\boxed{S_{n+1}=S_n+(n+1)!}

On the other hand, we have:

S_{n+1}=\sum\limits_{k=0}^{n+1}k!=0!+\sum\limits_{k=1}^{n+1}k!=1+\sum\limits_{k=1}^{n+1}k!=1+\sum\limits_{k=0}^{n}(k+1)!=\\\\\\=1+\sum\limits_{k=0}^{n}k!(k+1)=1+\sum\limits_{k=0}^{n}(k\cdot k!+k!)=1+\sum\limits_{k=0}^{n}k\cdot k!+\sum\limits_{k=0}^{n}k!\\\\\\(2)\qquad \boxed{S_{n+1}=1+\sum\limits_{k=0}^{n}k\cdot k!+S_n}

So from (1) and (2) we have:

\begin{cases}S_{n+1}=S_n+(n+1)!\\\\S_{n+1}=1+\sum\limits_{k=0}^{n}k\cdot k!+S_n\end{cases}\\\\\\&#10;S_n+(n+1)!=1+\sum\limits_{k=0}^{n}k\cdot k!+S_n\\\\\\&#10;(\star)\qquad\boxed{\sum\limits_{k=0}^{n}k\cdot k!=(n+1)!-1}

Now, let's try to calculate sum \sum\limits_{k=0}^{n}k\cdot k!, but this time we use perturbation method.

S_n=\sum\limits_{k=0}^nk\cdot k!\\\\\\&#10;\boxed{S_{n+1}=S_n+(n+1)(n+1)!}\\\\\\&#10;

but:

S_{n+1}=\sum\limits_{k=0}^{n+1}k\cdot k!=0\cdot0!+\sum\limits_{k=1}^{n+1}k\cdot k!=0+\sum\limits_{k=0}^{n}(k+1)(k+1)!=\\\\\\=&#10;\sum\limits_{k=0}^{n}(k+1)(k+1)k!=\sum\limits_{k=0}^{n}(k^2+2k+1)k!=\\\\\\=&#10;\sum\limits_{k=0}^{n}\left[(k^2+1)k!+2k\cdot k!\right]=\sum\limits_{k=0}^{n}(k^2+1)k!+\sum\limits_{k=0}^n2k\cdot k!=\\\\\\=\sum\limits_{k=0}^{n}(k^2+1)k!+2\sum\limits_{k=0}^nk\cdot k!=\sum\limits_{k=0}^{n}(k^2+1)k!+2S_n\\\\\\&#10;\boxed{S_{n+1}=\sum\limits_{k=0}^{n}(k^2+1)k!+2S_n}

When we join both equation there will be:

\begin{cases}S_{n+1}=S_n+(n+1)(n+1)!\\\\S_{n+1}=\sum\limits_{k=0}^{n}(k^2+1)k!+2S_n\end{cases}\\\\\\&#10;S_n+(n+1)(n+1)!=\sum\limits_{k=0}^{n}(k^2+1)k!+2S_n\\\\\\\\&#10;\sum\limits_{k=0}^{n}(k^2+1)k!=S_n-2S_n+(n+1)(n+1)!=(n+1)(n+1)!-S_n=\\\\\\=&#10;(n+1)(n+1)!-\sum\limits_{k=0}^nk\cdot k!\stackrel{(\star)}{=}(n+1)(n+1)!-[(n+1)!-1]=\\\\\\=(n+1)(n+1)!-(n+1)!+1=(n+1)!\cdot[n+1-1]+1=\\\\\\=&#10;n(n+1)!+1

So the answer is:

\boxed{\sum\limits_{k=0}^{n}(1+k^2)k!=n(n+1)!+1}

Sorry for my bad english, but i hope it won't be a big problem :)
8 0
4 years ago
Other questions:
  • A field test for a new exam was given to randomly selected seniors. The exams were graded, and the sample mean and sample standa
    15·1 answer
  • There are 42 carpenters in a crew. On a certain day, 36 were present. What percent showed up for work?
    12·2 answers
  • 10 mm<br>4 mm<br>u What is the volume of the cone to the nearest whole number?<br>​
    13·1 answer
  • Pablo is running a 15.5-kilometer race. which number sentence will tell how many meters pablo will run if he finishes the race?
    13·2 answers
  • Find the distance between the points given<br><br>(0, -6) and (9, 6)
    6·1 answer
  • Can you guys please help me
    15·2 answers
  • Please help ASAP PLEASE AND THANK YOUUU ❤️
    8·2 answers
  • Ellen had 25 hair clips.7 of them and the rest were purple , what precent of the hair clips were blue,what percent of the hair c
    5·1 answer
  • Omar drove 819 miles in 13 hours At the same rate, how many miles would he drive in 9 hours
    11·1 answer
  • Help me to answer 1b, solve the problem in detail, thank you
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!