What is the vertex form of # y= (9x-6)(3x+2)+4x^2+5x#?

1 Answer
Apr 25, 2017

#y=31(x+5/62)^2-1513/124#

Explanation:

#y=(9x-6)(3x+2)+4x^2+5x#

= #27x^2+18x-18x-12+4x^2+5x#

= #31x^2+5x-12#

= #31(x^2+5/31x)-12#

= #31(x^2+2xx5/62xx x+(5/62)^2-(5/62)^2)-12#

= #31(x+5/62)^2-31(5/62)^2-12#

= #31(x+5/62)^2-25/124-12#

or #y=31(x+5/62)^2-12 25/124#

i.e. #y=31(x+5/62)^2-1513/124#

and vertex is #(-5/62,-12 25/124)#

graph{y=31(x+5/62)^2-1513/124 [-3, 3, -20, 20]}