

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)