Answer: D. 10x^2 + 4x + 3
To find the combined area, add both of the areas together.
A = (3x^2 - x + 7) + (7x^2 + 5x - 4) (Remove the parentheses)
A = 3x^2 - x + 7 + 7x^2 + 5x - 4 (Combine the like terms)
A = 10x^2 + 4x + 3
∴ the combined area of Tiffany's fence and lawn is 10x^2 + 4x + 3.
