Question

?(21)+?(4)=300 what is the answer

Answer 1

`21x + 4y = 300`

We have infinitely many numbers that make this equation hold. For example:

`(x,y)=(69,-287.25) \\ (x,y)=(1,69.75) \\ (x,y)=(7,38.25)`

This could go on forever, so your question does not have a right answer.