Factoring

  Difference of two squares:   $\displaystyle x^2-y^2 = (x+y)(x-y)$      
  Difference/sum of two cubes:   $\displaystyle x^3\pm y^3 = (x\pm y)(x^2\mp xy+y^2)$      
  Difference of two fourth powers:   $\displaystyle x^4-y^4=(x^2-y^2)(x^2+y^2)=(x+y)(x-y)(x^2+y^2)$      
  Perfect square trinomial:   $\displaystyle x^2\pm 2xy+y^2 = (x\pm y)^2$      
  Factoring by Grouping:   $\displaystyle acx^3+adx^2+bcx+bd=ax^2(cx+d)+b(cx+d)=(ax^2+b)(cx+d)$      


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