Question 86313
multiply (x+2y)^4 
= 4C4x^4 + 4C3x^3(2y) + 4C2x^2(2y)^2 + 4C1x(2y)^3 + 4C0(2y)^4

= x^4 + 8x^3y + 24x^2y^2 + 32xy^3 + 16y^4

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Cheers,
Stan H.