1) -1,5(x+y)+x(x+y)-y(x+y)+(x+y) 2) (t+k)-8x(t+k) 3) (c+d)x-(c+d)y+5(c+d)+5xy(c+d)
1) =(x+y) (x-y+1-1,5)=(x+y)(x-y-0,5) 2) =(t+k) (1-8x) 3) =(c+d) (x-y+5+5xy)