Question

If - 4 $ 1 = 4,7 $- 7 = 49 and 3$1 - 3 than find the
value of -8$ -5 ?
(a) - 1
(b) 92
(c) - 49
(d) -69​

Answer 1

and how the answer is -40 I kept the solution in that pic plz see and thank u and my answer was deleted by someone if they thought that that is wrong .. I done by this method .. thank u