用乘法公式计算501²和9.9²

501²
=(500+1)²
=500²+1000+1²
=250000+1000+1
=251001

9.9²
=(10-0.1)²
=10²-2-0.1²
=100-2+0.01
=98.01
希望对你有帮助，不懂可以追问。

（500+1）²=500²+2*500*1+1²=250101
（10-0.1）²=10²+2*10*0.1+0.1²=102.01

501²
=(500+1)²
=(500+1)(500+1)
=500²+2x500+1²
=250000+1000+1
=251001


9.9²
=(10-0.1)²
=(10-0.1)(10-0.1)
=10²-2x10x0.1+0.1²
=100-2+0.01
=98.01

（500+1）^2=500^2+2*500+1,(10-0.1)^2=10^2-2*10*0.1+0.1^2

501²
=(500+1)²
=500²+2x500+1²
=250000+1000+1
=251001
9.9²
=(10-0.1)²
=10²-2x10x0.1+0.1²
=100-2+0.01
=98.01
不懂得欢迎追问...

501²=（500+1）²=500²+2x500+1=250000+1000+1=251001

9.9²=(10-0.1)²=10²-2x0.1x10+0.1²=100-2+0.01=98.01

501²=(500+1)²
=(500+1)(500+1)
=500*500+500+500+1
=251001

9.9²=(10-0.1)²
=(10-0.1)(10-0.1)
=10*10-1-1+0.01
=98.01