Question

x - 2(x + 10) = 12 what's x

Answer 1

Hello there! How are you today?

First, let's rewrite our problem.

x - 2(x + 10) = 12, solve for x.

To start us off, we need to apply the distributive property to the left side of the equation "-2(x + 10)", as since there is no sign between the number and the parenthesis, it is implied that we must multiply.

To distribute, we multiply the number outside of the parenthesis by all numbers inside the parenthesis.

For example;

2(1 + 3)
2(1) + 2(3)
2 + 6
8.

Now that we (hopefully) understand our concept, let's proceed to our equation to solve for x.

x - 2(x + 10) = 12

Apply the Distributive Property.

-2(x) - 2(!0)
-2x - 20.

We now have:

x - 2x - 20 = 12
Combine like-terms

-x - 20 = 12
Add 20 to both sides to isolate -x.

-20 + 20 = 0
12 + 20 = 32

Now we are left with:
-x = 32

However, we are not done as we still have x being multiplied by -1 (-x just means -1x). To get rid of the -1, we need to divide both sides by -1 to cancel them out.

-x / -1 = x
32 / -1 = -32

x = -32 is your solution.

I hope this helps!

Answer 2

Here are some things you should know when solving algebraic equations.
If you add an expression to both sides of an equation, the resulting equation will have the same solution set as the original equation. In other words, they will be equivalent. This is true for all operations. As long both sides are treated the same, the equation will stay balanced.
You will also need to know how to combine like terms. But what are like terms to begin with? Like terms are defined as two terms having the same variable(s) (or lack thereof) and are raised to the same power. In mathematics, something raised to the first power stays the same. So, 5x and 10x are like terms because they both have the same variable and are raised to the first power. You don’t see the exponents because it doesn’t change the value of the terms.
To combine like terms, simplify add the coefficients and keep the common variable(s) and exponent.
The distributive property is another important rule you will need to understand. The distributive property is used mostly for simplifying parentheses in expressions/equations.
For example, how would you get rid of the parentheses here?
6(x + 1)
If there wasn’t an unknown in between the parentheses, you could just add then multiply. That is what the distributive property solves. The distributive property states that a(b + c) = ab + ac
So, now we can simplify our expression.
6(x + 1) = 6x + 6

To sum up how to solve algebraic equations:

Use the distributive property if needed

Combine like terms on both sides of the equation if needed

If you do one operation on one side of the equation, do the same on the opposite side
x - 2(x + 10) = 12
x - 2x - 20 = 12 <-- Using the distributive property
-x - 20 = 12 <-- Combing like terms
-x = 32 <-- Add 20 to both sides
x = -32 <-- Divide both sides by -1

So, x is equal to -32.