А) x^2+10x+10-10x+5x^2= 6x^2+10
b) 5(a^2+2ab+b^2)-10ab=5a^2+10ab+5b^2-10ab=5a^2+5b^2
c) (c-2)(c+3)-(c^2-2c+1)=c^2-6-c^2-2c+1= -5-2c
d) 3(4-4x+x^2)-(2x^4-2x^3+x^2-x^2+5x^2+5x)+4x^2-x^4+8-2x^2=12-12x+3x^2-2x^4-2x^3-5x^2+5x+4x^2-x^4+8-2x^2=20-7x-2x^2-2x^3-3x^4