Solution
Step 1
Write an equation to use solve the problem
let the numbers be x and y
x + y =17 -------------(1)
y = x-3 ------------(2)
Step 2
Solve the equation to find x and y
From (1) y = 17-x
Substituting for y in equation yields
17-x=x-3
17+3 = x+x
20 = 2x
20/2 = 2x/2
x = 10
To find y we substitute for x in the equation
y = 17-10 = 7
Hence the smaller number is 7