Question

Expand and simplify the expression (7y+3x)².

A. 49y² + 42xy + 9x²
B. 49y² - 42xy + 9x²
C. 49y² + 6xy + 9x²
D. 49y² - 6xy + 9x²

Answer 1

To expand (7y+3x)², square each term and double the product of the two terms, resulting in 49y² + 42xy + 9x² which corresponds to answer choice A.

Step-by-step explanation:

To expand and simplify the expression (7y+3x)², we need to apply the formula (a+b)² = a² + 2ab + b². In this case, 'a' is 7y and 'b' is 3x.

Here's the step-by-step process:

1. Square 7y to get 49y².
2. Multiply 7y by 3x and then by 2 to get 42xy (because 2 · 7y · 3x = 42xy).
3. Square 3x to get 9x².
4. Combine these results to get the expanded and simplified expression: 49y² + 42xy + 9x².

The correct answer is A. 49y² + 42xy + 9x².