Question

If 2x - 5 = 15, what is the value of x?

• A. 4
• B. 5
• C. 10
• D. 20
• E. 40

Hint:

When solving two-step equations of the form \(ax+b=c\), always deal with the addition/subtraction part first (undoing \(b\)) before handling the multiplication/division part (undoing \(a\)).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
This is a two-step linear equation. To find the value of \(x\), we need to perform two inverse operations to isolate the variable.
Step 2: Key Formula or Approach:
1. Isolate the term containing \(x\) by adding or subtracting the constant term.
2. Solve for \(x\) by dividing by its coefficient.
Step 3: Detailed Explanation:
The equation is:
\[ 2x - 5 = 15 \]
First, add 5 to both sides to isolate the \(2x\) term:
\[ 2x - 5 + 5 = 15 + 5 \]
\[ 2x = 20 \]
Next, divide both sides by 2 to solve for \(x\):
\[ \frac{2x}{2} = \frac{20}{2} \]
\[ x = 10 \]
Step 4: Final Answer:
The value of \(x\) is 10, which corresponds to option (C).