How do you expand (2x+9)^2?
(2x+9)2 = (2x+9)(2x+9) Use FOIL to expand these brackets: First - (2x+9)(2x+9) --> 4x2 Outside - (2x+9)(2x+9) --> 4x2 + 18x Inside - (2x+9)(2x+9) --> 4x2 + 18x + 18x Last - (2x+9)(2x+9) --> 4x2 + 18x + 18x + 81 Therefore, (2x+9)(2x+9) = 4x2 + 18x + 18x + 81 = 4x2 + 36x + 81
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