Twelve decreased by twice a number equals -34. Write an equation for this situation and then find the number.

Question

math problem i cant solve.

Answer 1

"Decreased by" means you will subtract something from 12.

"Twice a number" means "two times a number," which means you are multiplying that number by 2.

"A number" should be represented by a variable — let's use the variable x.

Twelve decreased by...

12 -

Twelve decreased by two times a number...

12 - 2x

Twelve decreased by two times a number equals -34.

12 - 2x = -34

Now that we have our equation, let's solve for x! First, get rid of anything that isn't multiplying or dividing with x. That means we need to get rid of twelve. Whatever we do on one side of the equation, we have to do to the other, so subtract 12 from both sides.

12 - 2x = -34

-12. -12

-2x = -46

Now, to isolate x, we have to divide it by -2. Whatever we do on one side of the equation, we have to do to the other, to keep it equal. So divide both sides by -2.

-2x = -46

(-2x) / (-2) = (-46) / (-2)

x = 23

x=23 is your final answer.

Answer 2

Let's start by letting "the number" be the variable, x

12 decreased by twice a number becomes : 12 - 2x

This is equal to -34

So,

12 - 2x = -34

Subtract 12 from both sides

12 - 2x = -34

-12. -12

-2x = -48

divide both sides by -2

-2x = -48

---- -----

-2. -2

x = -24