Answer:
1. x³y² + 4x²y³ + 7y⁴ + x⁴
2. a² + b² + c² + 2ab + 2bc + 3ca
Step-by-step explanation:
1. x³y² + x²y³ + 3y⁴ and x⁴ + 3x²y³ + 4y⁴
= x³y² + x²y³ + 3y⁴ + x⁴ + 3x²y³ + 4y⁴
= x³y² + x²y³ + 3x²y³ + 3y⁴ + 4y⁴ + x⁴
= x³y² + 4x²y³ + 7y⁴ + x⁴
2. a² + 3ab - bc, b² + 3bc - ca and c² + 3ca - ab
= a² + 3ab - bc + (b² + 3bc - ca) + (c² + 3ca - ab)
= a² + 3ab - bc + b² + 3bc - ca + c² + 3ca - ab
= a² + b² + c² + 3ab - ab + 3bc - bc + 3ca - ca
= a² + b² + c² + 2ab + 2bc + 3ca
