Question

Steve has $3 more than twice as much as Tracy. Together they have $57. How much does each have?

Answer 1

Steve has 39$ and Tracy has 18$

Explanation:

Let x be Steve's money and y be Tracy's money
Steve has 3$ more than twice as much as Tracy
x = `2*y +3`
Rewrite this as
`x - 2*y =3`
together they have 57$
x + y = 57

Now we have to unknown (x, y) and two equation
`x -2*y =3` equation 1
`x+y = 57` equation 2
Subtract equation 2 once with equation 1
`x+y -(x-2*y)=57-3`
`3*y =54`
`y=54/3=18`
`x=57-y=57-18=39`

Note this is not the simplest way but it is more systematic and when you have more equations this method becomes better than the alternative.

Alternative solution (worse in my opinion)
x+y=57
x=57-y
`x-2*y=3`
`57-y-2*y=57-3*y=3`
`3*y=57-3=54`
`y=54/3=18`
`x=57-18=39`