How do you factor #25a ^ { 2} - 45a + 18#?

1 Answer
May 13, 2018

Answer:

#(5x-6)(5x-3)#

Explanation:

#25a^2-45a+18# = #25x^2-45x+18# which is in the general form #ax^2+bx+c#
(i changed the a to x so that the general form would work)

You can either use the "cross" method or the quadratic formula.

So for the quadratic formula which is

#x=(-b+-sqrt(b^2-4ac))/(2a)#

#x=(45+-sqrt(45^2-4*25*18))/(2*25)#

#x=(45+-sqrt(225))/50#

#x=(45+-15)/50#

#x=(45+15)/50# or #x=(45-15)/50#

#x=60/50# or #x=30/50#

#x=6/5# or #x=3/5#

#25x^2-45x+18 = (x-6/5)(x-3/5) = (5x-6)(5x-3)#