a) $A(x) + B(x) - C(x)= x^{2}-0.45x+1.2 + 0.8x^{2}-1.2x - (1.6x^{2}-2x)=0.2^{2}+0.35x+1.2$.
b) $M(y) - N(y) - P(y)=y^{2}-1.75y-3.2-(0.3y^{2}+4)-(2y-7.2)=0.7y^{2}-0.35y$.
a) $A(x) + B(x) - C(x)= x^{2}-0.45x+1.2 + 0.8x^{2}-1.2x - (1.6x^{2}-2x)=0.2^{2}+0.35x+1.2$.
b) $M(y) - N(y) - P(y)=y^{2}-1.75y-3.2-(0.3y^{2}+4)-(2y-7.2)=0.7y^{2}-0.35y$.