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
Advocard [28]
3 years ago
12

The difference of twelve times a number and nine times a number

Mathematics
2 answers:
inna [77]3 years ago
6 0

Since the problem states "a number" and again "a number", I assume it;'s the same number. Let the number be x.

12x - 9x = 3x

The difference of twelve times a number and nine times a number is three times the number.

Crank3 years ago
6 0

12x-9y

Difference means subtraction, so the difference between 12 <u>times a number</u> is known as 12x because we do not know what is being multiplied by 12. Same with 9 times a number. Since 12 and 9 have two numbers that we don't know the value of, we have to change one of them to a different variable because we do not know if it is the same number or not. So it would be 12x-9y, or any letters you choose.

You might be interested in
MATH HELP!!!!!<br><br> If y = 15 when x = 2, what is the value of x when y = 7?
Ede4ka [16]

<u>Direct Variation:</u>  \frac{y}{x} = k

\frac{15}{2} = k

when y = 7:      \frac{7}{x} = \frac{15}{2}

14 = 15x

\frac{14}{15} = x

<u>Inverse variation:</u>   y*x = k

15 * 2 = k

30 = k

when y = 7:      7 * x = 30

x = \frac{30}{7}


3 0
3 years ago
Solve for x. Your answer must be simplified. -7x &gt; 10
andre [41]
The answer to this is x < -10/7
5 0
2 years ago
A kayaker spends a morning paddling on a river. She travels 9 miles upstream and 9 miles downstream in a total of 6 hours. In st
tresset_1 [31]
To answer this item, we have 4 as the speed of the kayaker in still water and the speed of current be y.

When the karayaker moves upstream or against the current, his speed would be 4 - y. Further, if he moves downstream or with the current, the total speed would be 4 + y. The time utilized for the travel is equal to the ratio of the distance and the speed. 

 Total time = 9/(4 - y)  + 9/(4 + y) = 6

We multiply the equation by (4-y)(4+y)
              9(4-y) + 9(4 + y) = 6(4-y)(4+y)

Simplifying,
                72 = 96 - 6y²
Transposing all the constants to only one side of the equation and rearranging,
               6y² = 96 - 72
                 y² = 4
                    y = 2

Hence, the speed of the river's current is 2 miles/hr. <em>The answer is letter B.) 2 miles/hour.</em>
5 0
3 years ago
Jan is saving for a skateboard. She save $30 already which is 20% of the total price. How much does skateboard cost
Stolb23 [73]
The skateboard cost $150
3 0
3 years ago
A sphere of radius r is cut by a plane h units above the equator, where
Anika [276]
Consider the top half of a sphere centered at the origin with radius r, which can be described by the equation

z=\sqrt{r^2-x^2-y^2}

and consider a plane

z=h

with 0. Call the region between the two surfaces R. The volume of R is given by the triple integral

\displaystyle\iiint_R\mathrm dV=\int_{-\sqrt{r^2-h^2}}^{\sqrt{r^2-h^2}}\int_{-\sqrt{r^2-h^2-x^2}}^{\sqrt{r^2-h^2-x^2}}\int_h^{\sqrt{r^2-x^2-y^2}}\mathrm dz\,\mathrm dy\,\mathrm dx

Converting to polar coordinates will help make this computation easier. Set

\begin{cases}x=\rho\cos\theta\sin\varphi\\y=\rho\sin\theta\sin\varphi\\z=\rho\cos\var\phi\end{cases}\implies\mathrm dx\,\mathrm dy\,\mathrm dz=\rho^2\sin\varphi\,\mathrm d\rho\,\mathrm d\theta\,\mathrm d\varphi

Now, the volume can be computed with the integral

\displaystyle\iiint_R\mathrm dV=\int_0^{2\pi}\int_0^{\arctan\frac{\sqrt{r^2-h^2}}h}\int_{h\sec\varphi}^r\rho^2\sin\varphi\,\mathrm d\rho\,\mathrm d\varphi\,\mathrm d\theta

You should get

\dfrac{2\pi}3\left(r^3\arctan\dfrac{\sqrt{r^2-h^2}}h-\dfrac{h^3}2\left(\dfrac{r\sqrt{r^2-h^2}}{h^2}+\ln\dfrac{r+\sqrt{r^2-h^2}}h\right)\right)
5 0
3 years ago
Other questions:
  • Gloria traveled a total of
    5·1 answer
  • Graph f(x)=|x−2|+3 .<br><br> Use the ray tool to graph the function.
    7·1 answer
  • Verify the identity. cotangent x equals StartFraction 1 plus cosine 2 x Over sine 2 x EndFractioncot x= 1+cos2x sin2x Use the ap
    12·1 answer
  • 20 pts awarded and brainliest marked, plz help ASAP!!!!!!
    7·2 answers
  • The polynomial p(x)=3x^3-20x^2+37x-20 has a known factor of (x-4). Rewrite p(x) as a product of linear factors. p(x) =
    7·1 answer
  • The grocery store has a sale on canned tomatoes: 4 cans for $5.00. Find the unit rate (cost per can).​
    6·1 answer
  • What the answer please help marking brainliest if it's correct and explain​
    14·1 answer
  • Alexa can blow 15 balloons in 20 minutes. Sara can blow 18
    7·1 answer
  • Plss answer the question below
    15·1 answer
  • How many centimeters are in 28 ft? (1 ft = 12 in., 1 in. = 2.54 cm)<br> SOMEOnE HELP MEH PLEASE
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!