500²—1000x498+498² - 知识问答

500²—1000x498+498²

9个回答

5002-1000×498+4982
=5002-2×500×498+4982
=（500-498）2
=22
=4
x2+y2
=x2+2xy+y2-2xy
=(x+y)2-2xy
=(1/2)2-2×(1/8)
=1/4-1/4
0

相关问题