x-9 = 5 x = 5+9 x = 14
How about 5 x 9 x enough multiples of 10 to give you 5 digits? 5 x 9 = 45 5 x 9 x 10 = 450 5 x 9 x 10 x 10 = 4500 5 x 9 x 10 x 10 x 10 = 45000 18225
If you mean: x+8-x+9 when x = 5 Then it is: 5+8-5+9 = 17
9C5 = 9!/[(9 - 5)!5!] = 9!/(4!5!) = (9 x 8 x 7 x 6 x 5!)/(5! x 4 x 3 x 2 x 1) = 3 x 7 = 21
4
8x - 9 = 9x - 5 8x - 8x - 9 = 9x - 8x - 5 -9 = x - 5 -9 + 5 = x - 5 + 5 -4 = x
9 x 5 = 45
5 x (5 + 9) x 9 = 5 x 14 x 9 = 630
16 x 9 x 5 x 7 = 5040
9 x 5
x=9
You mean "What percentage is 90 million of 5 billion?" If so, [(90 x 10^6) x 100] / (5 x 10^9) = (9 x 10^9) / (5 x 10^9) = 9/5 = 1.8%