72 chicken and 4ó3 dogs come to 535 animals altogether.
Answer:
Step-by-step explanation:
Key to this method is remembering that

So, if you divide the coefficient of x by 2 and square it, that will complete the square. With that in mind, things are easy.
6/2 = 3, so add 

So, c=9
Similarly, for the other two,

You don't really have to worry about the sign, since squaring will always make it positive

Rather than trial and error, you can do this with an equation.
x + x+1 + x+2 = 267 =>
3x+3 = 267
x = 264/3 = 88
So the numbers are 88+89+90. 90 is the largest number.