Question

奥数，你会么？

如果a+c=15.2，a-c=10.8，求a.c是多少?

Answer 1

a+c-(a-c)=15.2-10.8
a+c-a+c=4.4 2c=4.4 c=2.2 a=15.2-2.2=13
a=13,c=2.2

Answer 2

a=13 b=2.2

Answer 3

a+c-(a-c)=15.2-10.8
a+c-a+c=4.4,2c=4.4,c=2.2,a=15.2-2.2=13
a=13,c=2.2

Answer 4

a=13
b=2.2