State which of the following are equations (with a variable). Give reason for your answer. Identify the variable from the equations with a variable.
`5 xx 4 - 8 = 2x`

Answer

To determine whether the expression \(5 \times 4 - 8 = 2x\) is an equation with a variable, we will follow these steps:

### Step 1: Identify the expression
The expression given is:
\[ 5 \times 4 - 8 = 2x \]

### Step 2: Check if it is an equation
An equation is defined as a mathematical statement that asserts the equality of two expressions. In this case, we have:
\[ 5 \times 4 - 8 \text{ on the left side and } 2x \text{ on the right side.} \]
Since there is an equal sign (=) present, this indicates that both sides of the expression are being compared for equality.

### Step 3: Verify both sides
Calculating the left side:
\[ 5 \times 4 = 20 \]
Then,
\[ 20 - 8 = 12 \]
So, the left side simplifies to 12.

Now, we have:
\[ 12 = 2x \]
This confirms that the expression is indeed an equation because it equates two values.

### Step 4: Identify the variable
In the equation \(2x\), the letter \(x\) represents the variable. A variable is a symbol (often a letter) that stands in for a number that can change or vary.

### Conclusion
Thus, we conclude that:
- Yes, \(5 \times 4 - 8 = 2x\) is an equation with a variable.
- The variable in this equation is \(x\).