$#Pi$
1, P(x)+Q(x) = (2x³+2x-3x²+1) + (3x²-5-2x³-x)
= 2x³+2x-3x²+1+3x²-5-2x³-x
= (2x-x) + (-3x²+3x²) + (1-5) + (2x³-2x³)
= -4+x
2, P(x)-Q(x) = (2x³+2x-3x²+1) - (3x²-5-2x³-x)
= 2x³+2x-3x²+1-3x²+5+2x³+x
= (2x+x) + (-3x²-3x²) + (1+5) + (2x³+2x³)
= 6+3x-6x²+4x³