Question

complete the square

Answer 1

Given the binomial x^2+6x, we observe that the a value is one (it is in this case) then we take half of b, square that, and add it to the expression to get\[x^2+6x+9=(x+3)^2\]

Answer 2

This process comes from \[(a \pm b)^2=a^2\pm2ab+b^2\]We observe what we have, and add what we need to make it meet the pattern immediately above.