a: \(A\left(x\right)=3x^4-5x^2+x^5+3x^2-4x^4+1\)
\(=x^5+\left(3x^4-4x^4\right)+\left(-5x^2+3x^2\right)+1\)
\(=x^5-x^4-2x^2+1\)
\(B\left(x\right)=5x^5-4x^4+2x^2+2x^4-5-3\)
\(=5x^5-2x^4+2x^2-8\)
b: A(x)+B(x)
\(=x^5-x^4-2x^2+1+5x^5-2x^4+2x^2-8\)
\(=6x^5-3x^4-7\)