The sum of two consecutive integer is 43

That is 22 and 21:

22 + 21 = 43

if we write equations to find them, we say, numbers are a and b, they are consecutive so:

b = a + 1

a + b = 43

we substitute one in the other equation:

a + (a + 1) = 43

2a = 42

a = 21

then

b = a + 1 = 21 + 1

b = 22

43/2=21.5

knowing x1+x2=43

21+22=43