How do you factor #0.09y^2 - 0.81#?

1 Answer
Nov 30, 2015

Answer:

#0.09y^2 - 0.81 = (0.3y+0.9)(0.3y-0.9)#

Explanation:

The difference of squares formula gives us
#a^2 - b^2 = (a+b)(a-b)#
(you can multiply this out to confirm)

#0.09y^2 = (0.3y)^2#
and
#0.81 = 0.9^2#

Thus, by the difference of squares formula

#0.09y^2 - 0.81 = (0.3y+0.9)(0.3y-0.9)#