Jawapan

2016-04-30T18:28:02+08:00
10/a= a/6.4
10/a- a/6.4=0
10(6.4)/a(6.4)-a(a)/6.4(a)=0
64/6.4a-a(a)/6.4a=0
64-a²/6.4a=0
64-a²=0
64= a²
a= √64
a= 8