1.) is 81 a multiple of 3? explain how you know
2.) is 46 a multiple of 4? explain how you know
3.) is 55 a multiple of 7? explain how you know.
4.) is 72 a multiple of 9? explain how you know.
5.) is 45 a multiple of 6? explain how you know.
also, write the numbers for each explanation. don't forget to write ''yes'' or ''no''.

Yes.a multiple of 3=add the numbers so 8 plus 1 is 9 and divide that by 3 it works
2.no.fthe number formed by its last two digits is divisible by 4, the original number is as well. 
3.no.take the last digit, double it, and subtract it from the rest of the number. 
4.yes.Add the digits. If that sum is divisible by nine, then the original number is as well.
5.no . has to work with both
Multiple of 2 --> is even (ends with 0, 2, 4, 6 or 8) 
Multiple of 3 --> digits add up to a multiple of 3. 

Ifound this on google “that means that the graph of a function with direct variation has these features: it is a straight line: because the slope is the ratio y/x = k. it passes through the origin (0,0): because y = kx = k (0) = 0.” i hope this you for what your looking for