Hello,
500=10^x
==> Log 500=xLog10
==>x=log 500
==>x=2,6989700043360188047862611052755...
Subtitute the pair (3,28) to x and y, if the result in right side is -8, then the pair is a solution to the equation
2x - y/2
= 2(3) - 28/2
= 6 - 14
= -8
The result is -8, so the pair (3,28) is a solution
$25 a month :) (its too short so i hope you have a lovely day)
Percent. Hope this helps!