Question

The solution to 13x = 78 is x = ___. (Only input whole number) Numerical Answers Expected! Answer for Blank 1:

Answer 1

Since you are trying to isolate $x$, you will need to remove the 13 through division:

$\dfrac{13x}{13} = \dfrac{78}{13}$

$\boxed{x = 6}$

Our answer is x = 6.

Answer 2

13x means "13*x" or "13 times x". The x is just a placeholder for a number. Think of it as a box. Inside the box will go the number we want. Which number is it? At this point we don't know.

We want a number that will multiply with 13 to get 78.

We could use trial and error to find the unknown number:

13 times 1 = 13

13 times 2 = 26

13 times 3 = 39

13 times 4 = 52

and so on

As you can see, this would take a while. And it's not a guarantee we'll actually find the solution this way.

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A much better method is to use algebra. We want to solve for x, or isolate it.

In other words, we need x on its own side. To do this, we undo the multiplication.

Division is the opposite of multiplication. Divide both sides by 13 to undo the "multiply by 13" operation done to x.

13*x = 78

13*x/13 = 78/13 ... dividing both sides by 13

x = 6

So the unknown number mentioned earlier is now known to be 6

The equation

13 times x = 78

turns into

13 times 6 = 78

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Answer: 6