JAMB - Mathematics (2009 - No. 1)
If 55\(_x\) + 52\(_x\) = 77\(_{10}\) find X
5
6
7
10
คำอธิบาย
5 \(\times\) x\(^1\) + 5 \(\times\) x\(^0\) + 5 \(\times\) x\(^1\) + 2 \(\times\) x\(^0\) = 77
(change all to base 10)
5x + 5 + 5x + 2 = 77
10x + 7 = 77
10x = 77-7
10x = 70
x = 70/10
x = 7