Final answer:
The expression 42(5x+3) simplifies to 210x + 126.
Step-by-step explanation:
The expression 42(5x+3) can be simplified using the distributive property of multiplication over addition. We distribute the 42 to both terms inside the parentheses, resulting in 210x + 126. Therefore, the simplified form of 42(5x+3) is 210x + 126.
Learn more about Simplifying expressions using the distributive property