By commutative property of equality, the expression 2ab² + (ab - 1) is equal to which of the following expressions? C. x² - 2xy + y² D. -20x¹y² + 30y4z² +40x²z4 D. 3r² +17rs - 11s² C. (ab - 1) + 2ab² D. x² 12xy + y² C. 2r²+7rs-3s² D. (2ab² + ab) - 1 38. What is the simplified form of the polynomial -7xy + x² + y² + 5xy? A. -20x¹y2-30y¹z² - 40x²z4 C.-20x¹y² + 30y4z² - 40x²z¹ B. -20x¹y²-30y¹z² + 40x²z4 A. 2ab² + (ab - 1) B. 2ab² + ab - 1 A. x² + 2xy + y² B. x² + 12xy + y² 39. Determine the product of -10xyz and 2x³y - 3y³z + 4xz³. 40. What is the sum of the polynomials (5rs - ² - s²) and (7s² - 12rs +3r²)? A. 2r²-7rs +3s² B. 3r²-17rs + 11s²