Find the coefficient of x^4 in (1-x)^2 (2+x)^5
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(1-x)^2(2+x)^5
=(1-x)^2(2+x)^2 (2+x)^3
=(1+x^2-2x)(4+x^2+4x)(8+x^3+12x+6x^2)
=(4+x^4+4x^2+4x-2x^3-8x^2)(x^3+6x^2+12x+8)
=(4+x^4-4x^2+4x-2x^3)(x^3+6x^2+12x+8)
=4x^3+24x^2+36x+32+x^7+6x^6+12x^5+8x^4-4x^5-24x^4-36x^3-32x^2+4x^4+24x^3+36x^2+32x-2x^6-12x^5-24x^4-16x^3
= -36x^4
And vl be -36
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