All categories

2 years ago

if the sum of a number and seven is doubled, the result is eight less than the number. Find the number

Mathematics

2 answers:

Kipish [7]2 years ago

5 0

Answer:

-22

Step-by-step explanation:

The result is eight less than the number means that

the result = number - 8

( x + 7 ) * 2 = x - 8

=> 2x + 14 = x - 8

=> x = -22

Alexeev081 [22]2 years ago

4 0

Answer: -18

Step-by-step explanation:

Let the number be represented by x.

If the sum of a number and seven is doubled, the result is four less than the number. The expression would be

2(x + 7) = x - 4

We would open the bracket on the left hand side of the equation by multiplying each term inside the bracket by 2. It becomes

2x + 14 = x - 4

Subtracting 14 and x from the left hand side and the right hand side of the equation, it becomes

2x + 14 - 14 - x =x - x - 4 - 14

x = - 18

You might be interested in

Find the sum of the geometric series 512+256+ . . .+4

mario62 [17]

$\bf 512~~,~~\stackrel{512\cdot \frac{1}{2}}{256}~~,~~...4$

so, as you can see above, the common ratio r = 1/2, now, what term is +4 anyway?

$\bf n^{th}\textit{ term of a geometric sequence}\\\\a_n=a_1\cdot r^{n-1}\qquad \begin{cases}n=n^{th}\ term\\a_1=\textit{first term's value}\\r=\textit{common ratio}\\----------\\r=\frac{1}{2}\\a_1=512\\a_n=+4\end{cases}$

$\bf 4=512\left( \cfrac{1}{2} \right)^{n-1}\implies \cfrac{4}{512}=\left( \cfrac{1}{2} \right)^{n-1}\\\\\\\cfrac{1}{128}=\left( \cfrac{1}{2} \right)^{n-1}\implies \cfrac{1}{2^7}=\left( \cfrac{1}{2} \right)^{n-1}\implies 2^{-7}=\left( 2^{-1}\right)^{n-1}\\\\\\(2^{-1})^7=(2^{-1})^{n-1}\implies 7=n-1\implies \boxed{8=n}$

so is the 8th term, then, let's find the Sum of the first 8 terms.

$\bf \qquad \qquad \textit{sum of a finite geometric sequence}\\\\S_n=\sum\limits_{i=1}^{n}\ a_1\cdot r^{i-1}\implies S_n=a_1\left( \cfrac{1-r^n}{1-r} \right)\quad \begin{cases}n=n^{th}\ term\\a_1=\textit{first term's value}\\r=\textit{common ratio}\\----------\\r=\frac{1}{2}\\a_1=512\\n=8\end{cases}$

$\bf S_8=512\left[ \cfrac{1-\left( \frac{1}{2} \right)^8}{1-\frac{1}{2}} \right]\implies S_8=512\left(\cfrac{1-\frac{1}{256}}{\frac{1}{2}} \right)\implies S_8=512\left(\cfrac{\frac{255}{256}}{\frac{1}{2}} \right)\\\\\\S_8=512\cdot \cfrac{255}{128}\implies S_8=1020$

7 0

4 years ago

****EASY**** What are ratios equivalent to 5:8? blank:56 45:blank

TEA [102]

Answer:

10:16

Step-by-step explanation:

There are many equivalent ratios but I chose this one because the c value is 2.

7 0

3 years ago

An apartment has

kifflom [539]

810/10.8 = 75 ...so as the answer

5 0

3 years ago

Wyatt is making a salad using tomatoes, cucumbers, and carrots. This table gives the cost, per kilogram, of each ingredient, and

Lina20 [59]

According to the given information, we build the equation for the cost. After we build the equation, the equation that relates these measures is:

$C = 0.99 + xy + 0.2z$

Cost:

0.3 kilograms of tomatoes, at 3.30 dollars per kilogram.

Thus, the cost starts at:

$C = 0.3*3.3 = 0.99$

y kilograms of cucumbers, at x dollars per kilogram.

Considering this, the cost will now be of:

$C = 0.99 + xy$

0.2 kilograms of carrots, at z dollars per kilogram:

Now, we have to consider this for the cost, so:

$C = 0.99 + xy + 0.2z$

A similar example is given at brainly.com/question/14544759

8 0

3 years ago

Is the graph below proportional or non-proportional? How do you know?

Alex

Answer: Proportional

Step-by-step explanation: To determine whether x and y have a proportional relationship, see if the line through these points passes through the origin (0, 0). The points are on a line that passes through the origin. So, x and y have a proportional relationship

4 0

3 years ago