Final answer:
To solve the expression, simplify the square roots and combine like terms to get 13√7.
Step-by-step explanation:
To solve the expression, we need to simplify each square root individually and then add them. The square root of 28 can be simplified to √4 x √7, which equals 2√7. The square root of 63 can be simplified to √9 x √7, which equals 3√7. Therefore, the expression becomes 5(2√7) + 3√7. Combining like terms, we get 10√7 + 3√7, which equals 13√7. So, the final answer is 13√7.
Learn more about Simplifying square roots