281 X(x+2) 2(2x²+1) 4(1-2x²) 2(2-3x²) 3(5+1x²) 7(2+1x²) 3(-1+4x) 4x²(2+x) 283 x(a+b) a(m-nk) xy(x-y) p2q(q2-p) abc(a+b+c) xy2z2(xz-y+x3yz3) 2mn(n2-2m-3mn2) 2p2q2(3p2q-4q+5p) a2(1-4a2+5a3) x2(3-x42x6) 287 c=3 c=7 d=15x6y4,c=2y2 d=2m5n2,c=6m5n6 288 a+c x-y 2+x x-2 2x+1 3x-2y 289 a(m+n)+2(m+n) 3(x+y)-a(x+y) m(a-b)+(a-b) a(p-q)-b(p-q) 3(x+2y)+(x-2y)=(3+1)(x-2y)=4(x-2y)