Question #e86f9

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Answer 1 · 2017-11-03T04:03:08

#(8+9d)(8-9d)#

Now this expression is a difference of squares.

Statistics Lecture

We know this because #64# is a squared number #(8^2)#, while #81# is equal to #9^2#, and #d^2# is equal to #(d)^2#

If we apply this to our expression...

#64-81d^2#

#=(8+9d)(8-9d)#

Hope this helps :)

Answer 2 · 2017-11-03T04:06:00

#64-81d^2=color(blue)((8+9d)(8-9d)#

Factor:

#64-81d^2#

The two terms in this expression are square numbers.

#64=color(red)(8^2#

#81d^2=color(green)((9d)^2#

Factor the expression using the difference of squares:

#a^2-b^2=(a+b)(a-b)#

#color(red)(8^2)-color(green)((9d)^2)##=color(blue)((8+9d)(8-9d)#