Question 198002
(x+y)^4=(x+y)^2*(x+y)^2
(x+y)^2
x+y
x+y Multiply.
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x^2+2xy+y^2
x^2+2xy+y^2 Multiply
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x^4+2x^3y+x^2y^2+2x^3y+4x^2y^2+2xy^3+x^2y^2+2xy^3+y^4
x^4+4x^3y+6x^2y^2+4xy^3+y^4 ans.