Twelve decreased by twice a number equals -34

Question

I need help really really really really badly

Answer 1

Hi.  Decreased by means you are going to subtract.  So you would start with "12 -"

Twice a number means you are multiplying the number by 2.  You don't know the number so you assign it a variable.  Let's call it x.  So now we have "12 - 2x". 

The answer to our equation is -34 (given by equals -34.) 

To put it all together you have

12-2x = -34

To solve you can subtract 12 from both sides which gives you:

-2x = -46

Then divide both sides by -2.  This gives you 

x = 23

Hope this helps.

Janese

Answer 2

If you replace "a number" with x, you can write an algebraic equation to solve for x.

 

Twelve decreased by twice a number equals -34 

 

12  -  2x =  -34

 

We need the "x" term alone, so we subtract 12 from both sides:

 

- 2x = -46

 

Now, to solve for x, we divide each side by -2.

 

x = 23

 

So, the number is 23. 

 

Check:

 

12 - 2(23) = -34

12 -  46 = -34

 

Yes, this is true!