What are the integers a and b if their sum equals 57 and we know that b is 3 less than double of a?

Given that the sum of the integers a and b is
57.

==> a + b= 57
............(1)

We are given that b is 3 less than double
a.

==> Then we will rewrite :

b=
2a - 3 ...............(2)

Now, using the substitution method, we
will substitute (2) into (1).

==> a + (2a-3) =
57

==> 3a - 3 = 57

We will add 3
to both sides.

==> 3a =
60

==> a = 60/3 = 20

==>
b= 2a-3 = 2*20 -3 = 40-3 = 37

==> Then the
numbers are : a = 20 and b = 37.