Question

twice the sum of -2 and a number is the same as the number decreased by 7/8 find the number

Answer 1

We will have that the expression is:

$2(n-2)=n-\frac{7}{8}$

Now, we operate:

$\Rightarrow2n-4=n-\frac{7}{8}\Rightarrow n=-\frac{7}{8}+4$$\Rightarrow n=\frac{25}{8}\Rightarrow n=3.125$

So, the number is 3.125.

***Explanation***

We are told that twice the sum of -2 and a number equals something, now, the sum of a number [That we are going to call "n"] and -2 is the following:

$n-2$

[Remember that when we add a number and a negative number we will write the negative value in the sum, subtraction is the sum of a negative number]. Now, we are told that is twice that number, so it is then:

$2(n-2)$

We are also told that that expression is equal to the number "n" decrease by 7/8, that is:

$n-\frac{7}{8}$

Finally, we equal both expressions and obtain the value that is described in the text:

$2(n-2)=n-\frac{7}{8}$

And to determine the value of "n" we simply operate like terms and leave "n" alone on one side.