# One-Step Equations and Inverse Operations

## Key Questions

• They are helpful for solving with respect to a variable: if after some step you find yourself in a situation such as $\setminus \cos \left(x\right) = 0.7$, if you want to find the value of $x$ for which this statement is true, you need to apply the inverse cosine function at both sides and obtain $x = \setminus {\cos}^{- 1} \left(0.7\right)$

Substitute the solution for the variable in the equation and see if both sides of the equation are equal.

#### Explanation:

For example:

$x + 9 = 12$

Subtract $9$ from both sides.

$x = 12 - 9$

$x = 3$

Now check by substituting $3$ for $x$ into the equation and solve.

$3 + 9 = 12$

$12 = 12$ Check!

• A one-step equation is an equation that requires only one step to arrive at its solution.

I hope that this was helpful.