(4x²-7x+3)-(x²-8x+11)=(4x²-7x+3)+(-x²+8x-11)=
=4x²-7x+3-x²+8x-11=4x²-x²-7x+8x+3-11=3x²+x-8
(9m²-5m+4)-(-10m+m³+5)=(9m²-5m+4+(10m-m³-5)=
=9m²-5m+4+10m-m³-5=-m³+9m²+5m-1
(4x²-7x+3)-(x²-8x+11)=(4x²-7x+3)+(-x²+8x-11)=
=4x²-7x+3-x²+8x-11=4x²-x²-7x+8x+3-11=3x²+x-8
(9m²-5m+4)-(-10m+m³+5)=(9m²-5m+4+(10m-m³-5)=
=9m²-5m+4+10m-m³-5=-m³+9m²+5m-1