Whats 12 = -1x + 1 ? And how to solve it?

Question

So we have been having algebra for some time now and i don't really understand how to solve them cause i never understand the teacher.

sorry for my bad english :/ im swedish and im 14 :)

Answer 1

In algebra equations like this one, you can do the same thing to both sides to solve the problem. Solving a problem means that you must get the variable (in this case "x") on its own so that it has no numbers next to it or on the same side of the equal sign. Here's how you do this one:

12 = -1x + 1

First we want to get rid of the 1 on the right side so we subtract 1 from both sides and the 1 and -1 on the right cancel out.

12 - 1 = -1x + 1 - 1

Since 12 - 1 = 11 and 1 - 1 = 0, we now have:

11 = -1x

Now we want to get rid of the -1 next to the x. Since it looks like this, -1x, we know that it means -1*x because when a regular number is next to a variable that means they are being multiplied together. To cancel out the multiplication, we divide by the same number (make sure to do it to both sides):

11/(-1) = (-1x)/(-1)

The -1s on the right cancel out and we find that 11 divided by -1 is -11. We are left with:

-11 = x

So the answer is x = -11.

 

Answer 2

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Answer 3

Adding to Matt,

He is correct by making you work out the mechanics yourself.  I will give you an example problem, which is similar to yours.  This will give you a guideline.  Solve : 5x - 19 = 31 for x.

You will have to use your algebra skills to solve this kind of equation, which involves understanding how to manipulate the numbers to solve for the unknown.  First, I would put the unknown (x) on one side of the equation, and everything else on the other side. 

5x = 31 + 19 = 50------> Adding 19 from the left side, making sure to do the same operation to both sides.

then, I need to simply solve for x.

x = 50/5 = 10----> by dividing 5, you get the solution. 

Truxton Boyce

University of Delaware