SubArea: Polynomials and fractionsLevel: AProject ID: 9000101601Source Problem: 2010001301Accepted: 1Clonable: 1Easy: 0Expand (1+x)(x2+x−1)(1−x).−x4−x3+2x2+x−1x4−x3+2x2+x+1−x4+x3−1x4+x3−2x2+x−1