9514 1404 393
Answer:
g = 12
Explanation:
You recognize that 144 is 12², so you check to see if the x-coefficient is 2·12. It is. The quadratic is a square:
(g -12)² = 0
The only solution is the one that makes the squared term equal to zero:
g -12 = 0
g = 12
_____
The square of a binomial is ...
(a +b)² = a² +2ab +b²
Here, we have a=x, b=-12.