:(p²+q²)²-4p²q²=____________
=(p²+q²+2pq)(p²+q²-2pq)
=(p+q)²(p-q)²
1.25×14²-125×8.6²
=125×1.4²-125×8.6²
=125×(1.4²-8.6²)
=125×(1.4+8.6)(1.4-8.6)
=125×10×(-7.2)
=-9000
:(p²+q²)²-4p²q²=____________
=(p²+q²+2pq)(p²+q²-2pq)
=(p+q)²(p-q)²
1.25×14²-125×8.6²
=125×1.4²-125×8.6²
=125×(1.4²-8.6²)
=125×(1.4+8.6)(1.4-8.6)
=125×10×(-7.2)
=-9000