To solve the equation [tex]\( 2x + 3 = 21 \)[/tex] for [tex]\( x \)[/tex], follow these steps:
1. Isolate the term with the variable [tex]\( x \)[/tex]:
Start by subtracting [tex]\( 3 \)[/tex] from both sides of the equation to get rid of the constant term on the left side.
[tex]\[
2x + 3 - 3 = 21 - 3
\][/tex]
Simplifying this, we obtain:
[tex]\[
2x = 18
\][/tex]
2. Solve for [tex]\( x \)[/tex]:
Next, divide both sides of the equation by [tex]\( 2 \)[/tex] to isolate [tex]\( x \)[/tex].
[tex]\[
\frac{2x}{2} = \frac{18}{2}
\][/tex]
Simplifying this, we get:
[tex]\[
x = 9
\][/tex]
So, the solution to the equation [tex]\( 2x + 3 = 21 \)[/tex] is [tex]\( x = 9 \)[/tex].
Thus, the correct answer is:
(C) [tex]\( x = 9 \)[/tex]