We are given the formula: a*b=(a+b−1)2−1 Substituting the values a=1 and b=2 in the formula: (1*2)=(1+2−1)2−1=(2)2−1=4−1=3 Now, substitute these values into the next part of the expression (3*3) : 3*3=(3+3−1)2−1=(5)2−1=25−1=24 Thus, the answer is 675 . Therefore, the correct answer is (2) 675 . Quick Tip When solving problems with complex formulas, break the expression into smaller parts to solve step by step.