Question 85 (c)
Evaluate 125×52×a7103×a4
We have 125×52×a7103×a4=53×52×a7(2×5)3×a4=53+2×a723×53×a4=55×a723×53×a4=55−3×a7−423=52×a323=25a38
Question 85 (f)
Evaluate 154×18333×52×122
Suppose a2,a3,a4,a5,a6,a7are integers such that 57=a22!+a33!+a44!+a55!+a66!+a77! where 0 ≤ a< j for j= 2,4,5,6,7.
The sum a2+a3+a4+a5+a6+a7 is
Question 85 (a)
Evaluate 78×a10b7c1276×a8b4c12