Odpowiedź:
a)7(x2-2x+3)-1/2(14x2-8x+6)= 7x2-14x+21-7x2+4x-3= 14x2-10x+18= 14*(-1,1)2-10*(-1,1)+18=16.94-11+18=23.94
b) x(3xy+4y) - y(4x2-2y)= 3x2y+4xy-4x2y+2y2= xy+4xy+2y2= 5xy+2y2= 5*(-0,5)*(10)+2*10 2= -2,5*10+200= - 25+200= 75
