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solve : 3\8x-8=-7?

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3 Answers

I am thinking that this problem is stumping you because of the fraction 3/8.  It is a common problem for people.  Just remember that when you get the number with a variable alone on one side, all that you have to do is multiply both sides by the inverted number that is with the variable.  In this case, 3/8x would be multiplied by 8/3, so that 1x or x is what is left.

            8/3 x 3/8x = 1 x 8/3

            x = 8/3

To show you a different example, let's use a whole number.  If the problem had been 3x - 8 = -7, then you would be doing 3x = 1.  Think of the whole number 3 as being 3/1, so when you invert it, it would be 1/3. So, 1/3 x 3x = 1 x 1/3; thus, x = 1/3. 

Don't let the fraction or whole number throw you.  If you always think of the number that is with the variable as a fraction, then it is easier to see how it can be inverted.

I hope this helps.

The easiest way is to re-write the equation so it is easier to follow.

(3/8x) -8 = -7

if we add "8" to both sides of the equation, we get:

(3/8x) = 1

We then multiply each side of the equation by 8/3:

x = 8/3

By following through on the division, we see that:

x = 2 2/3  

I would take this a step further since your answer is an improper fraction (the numerator is larger than or equal to the denominator).

8/3 = 3/3 + 3/3 + 2/3

      =   1 + 1 + 2/3

      = 2 2/3


True - though 8/3 might be easier to work with if this part of a system of equations