Select the correct algebraic expression.
Answer & explanation
Correct answer: option 1
Put the value of a and b = 1 in all the given equations and satisfy
= ab - a - b + 1 = (a - 1) (b - 1)
1 - 1 - 1 + 1 = (1 - 1) (1 - 1) = 0
= ab + a - b + 1 = (1 - a) (1 - b) (1 - a) (1 + b)
1 + 1 - 1 + 1 = (1 - 1) (1 - 1) (1 - 1) (1 + 1)
2 ≠ 0
= ab + a + b + 1 = (1 - a) (b - 1)
1 + 1 + 1 + 1 = (1 - 1) (1 - 1)
4 ≠ 0
= ab - a - b + 1 = (a + 1) (1 + b)
1 - 1 - 1 + 1 = (1 + 1) (1 + 1)
0 ≠ 4