The correct option is A x3−3x2+5x−1
3x[x2+1]−[2x(x2+x−1)+1]−x2
We need to follow BODMAS rule.
=> Brackets (parts of a calculation inside brackets always come first).
=> Orders (numbers involving powers or square roots).
=> Division.
=> Multiplication.
=> Addition.
=> Subtraction.
3x[x2+1]−[2x(x2+x−1)+1]−x2
= 3x.x2+3x.1−[2x.x2+2x.x−2x.1+1]−x2
= 3x3+3x−2x3−2x2+2x−1−x2
= x3−3x2+5x−1