Question 355 of 480
What is the simplified form of the expression \( \sqrt{50} + \sqrt{18} \)?
- \( 7\sqrt{2} \)
- \( 5\sqrt{2} + 3\sqrt{2} \)
- \( 4\sqrt{2} \)
- \( 8\sqrt{2} \)
Correct Answer:
B
Explanation
To simplify the expression \( \sqrt{50} + \sqrt{18} \), we will break down each square root into its simplest form and then combine like terms.
### Step 1: Simplifying \( \sqrt{50} \)
1. **Factor 50**:
- The prime factorization of 50 is \( 2 \times 25 \).
- We can express this as \( 50 = 2 \times 5^2 \).
2. **Apply the square root**:
- Using the property of square roots, \( \sqrt{a \times b} = \sqrt{a} \times \sqrt{b} \), we can write:
\[
\sqrt{50} = \sqrt{2 \times 25} = \sqrt{2} \times \sqrt{25}
\]
- Since \( \sqrt{25} = 5 \), we have:
\[
\sqrt{50} = 5\sqrt{2}
\]
### Step 2: Simplifying \( \sqrt{18} \)
1. **Factor 18**:
- The prime factorization of 18 is \( 2 \times 9 \).
- We can express this as \( 18 = 2 \times 3^2 \).
2. **Apply the square root**:
- Again using the property of square roots:
\[
\sqrt{18} = \sqrt{2 \times 9} = \sqrt{2} \times \sqrt{9}
\]
- Since \( \sqrt{9} = 3 \), we have:
\[
\sqrt{18} = 3\sqrt{2}
\]
### Step 3: Combine the simplified square roots
Now that we have simplified both square roots, we can combine them:
\[
\sqrt{50} + \sqrt{18} = 5\sqrt{2} + 3\sqrt{2}
\]
### Step 4: Combine like terms
Since both terms contain \( \sqrt{2} \), we can add the coefficients:
\[
5\sqrt{2} + 3\sqrt{2} = (5 + 3)\sqrt{2} = 8\sqrt{2}
\]
### Final Answer
Thus, the simplified form of the expression \( \sqrt{50} + \sqrt{18} \) is:
\[
\boxed{8\sqrt{2}}
\]
### Explanation of Options
- **Option A: \( 7\sqrt{2} \)**: This is incorrect because it does not account for the correct addition of the coefficients from \( 5\sqrt{2} \) and \( 3\sqrt{2} \).
- **Option B: \( 5\sqrt{2} + 3\sqrt{2} \)**: While this expression is correct in its form, it is not the final simplified answer. It represents the intermediate step before combining like terms.
- **Option C: \( 4\sqrt{2} \)**: This is incorrect as it underestimates the sum of the coefficients from the two square roots.
- **Option D: \( 8\sqrt{2} \)**: This is the correct final answer, as we have shown through the simplification process.
### Common Pitfalls
- **Not simplifying square roots fully**: Always ensure to break down square roots into their prime factors to find the simplest form.
- **Forgetting to combine like terms**: When adding square roots, ensure that you only add the coefficients of like terms (those with the same radical).
- **Miscalculating coefficients**: Double-check the arithmetic when adding coefficients to avoid errors.
### Revision Summary
- Simplify square roots by factoring into prime components.
- Combine like terms carefully when adding square roots.
- Always check your final answer against the options provided.
- Understand the properties of square roots to avoid common mistakes.