a(5-3a)+1-a²(4a-3) 5{xy(x-2y)+z}-4{2z+xy(3x-y)} a(5-3a)+1-a²(4a-3) 5{xy(x-2y)+z}-4{2z+xy(3x-y)}

a(5-3a)+1-a²(4a-3) 5{xy(x-2y)+z}-4{2z+xy(3x-y)} a(5-3a)+1-a²(4a-3) 5{xy(x-2y)+z}-4{2z+xy(3x-y)}

a(5-3a)+1-a 2(4a-3)=5a-3a 2+1-4a*a 2+3a 2=-4a(3 차방)+5a+1
5{xy(x-2y)+z}-4{2z+xy(3x-y)} =5x 2y-10xy 2+5z-8z-15x 2y+5xy 2
=-10x 2y-5xy 2-10xy 2-3z
=-5xy(2x+y+2y)-3z