Answer:
The value of x is 21
Explanation:
2x+21 is a linear equation with one unknown, x. To solve for x, we can use the following steps:
1. Subtract 21 from both sides of the equation. This will isolate x on the left-hand side of the equation.
```
2x+21 - 21 = x
```
2. Divide both sides of the equation by 2. This will divide both sides of the equation by 2, which will cancel out the 2 on the left-hand side of the equation, leaving x by itself.
```
x = (2x+21)/2
```
3. Simplify the right-hand side of the equation.
```
x = x/2 + 21/2
```
4. Combine like terms on the right-hand side of the equation.
```
x = (1/2)x + 21/2
```
5. Subtract (1/2)x from both sides of the equation. This will isolate x on the left-hand side of the equation.
```
x - (1/2)x = (1/2)x + 21/2 - (1/2)x
```
6. Simplify the right-hand side of the equation.
```
(1/2)x = 21/2
```
7. Multiply both sides of the equation by 2. This will multiply both sides of the equation by 2, which will cancel out the (1/2) on the left-hand side of the equation, leaving x by itself.
```
2*(1/2)x = 21/2 * 2
```
8. Simplify the right-hand side of the equation.
```
x = 21
```
Therefore, the value of x is 21.