J.R. S. answered 02/19/18
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Do this like the one I did in your previous question.
Compare trial 3 to 1 where A triples, B stays the same and rate triples (1st order in A)
Compare trial 1 to 1 where B doubles, A stays the same and rate increases by 4 times (2nd order in B)
Order overall is the sum.
Rate expression is rate = k[A][B] each raised to the order determined above. You should be able to do that.
To find value of k, pick any rate and the associated [A] and [B] and plug these numbers into the rate expression and solve for k. The units should come out 1/M2hr or M-2hr-1