add the following polynomial
1.) (5x⁴ – 3x² + 4) + (6x³ – 4x² –7)
2.) –7x³y + 4x²y² – 2 and 4x³y + 1 – 8x²y²
3.) (5 + 24y³ - 7y²) + (-6y³ + 7y² + 5)
4.) (2x⁵ - 6x³ - 12x² -4) + (-11x⁵ + 8x + 2x² + 6)
5.) (3y⁵ - 2y + y⁴ + 2y³ + 5) and (2y⁵ + 3y³ + 2+ 7)​