How do you find the product #(2c-9d)^2#?

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Answer 1 · 2017-01-21T16:57:35

# 4c^2 -36cd + 81d^2#

#(2c - 9d)^2 = 4c^2 -36cd + 81d^2#

Answer 2 · 2017-01-21T17:01:12

Use the FOIL method as you would for any other binomial. Details follow

This is the same as #(2c-9d)(2c-9d)# and involves the multiplication of four products.

First: #(2c)*(2c) = 4c^2#

Outside: #(2c)*(-9d)=-18cd#

Inside: #(-9d)*(2c)=-18cd#

Last: #(-9d)*(-9d)=81d^2#

Add it all up:

#4c^2-36cd+81d^2#

Answer 3 · 2017-01-21T17:26:24

#4c^2-36cd+81d^2#

Given:#" "(2c-9d)^2" "->" "color(blue)((2c-9d)color(red)((2c-9d))#

Multiply everything in the second bracket by everything in the first

#color(red)(color(blue)(2c)(2c-9d) color(blue)(-9d)(2c-9d))#

#4c^2-18cd-18cd+81d^2#

#4c^2-36cd+81d^2#