(A-3)*(A+3)-(2-A)^2 = A^2 - 9 - ( 4 - 4A + A^2) = A^2 - 9 - 4 + 4A - A^2 = 4A - 13
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(2A+3B)*(3B-2A) - (A-B)*(B+A) = 9B^2 - 4A^2 - A^2 + B^2 = -5A^2 + 10B^2
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(X-2)*(X+2)*(X-3)*(X+3) = (X^2 - 4)*(X^2 - 9) = X^4-9X^2 -4X^2 + 36 = X^4 - 13X^2 + 36
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(5-A)^2 - (A+1)^2 +5*(2-A)*(2+A) = 25-10A+A^2-(A^2+2A+1)+5*(4-A^2) = -5A^2 - 12A + 44