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

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

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

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

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