Learning curve sum query

I have a doubt in one of the questions in learning curve...I noe its simple but im unable 2 remember how i had solved it earlier.Eg.

Step 1  y=a x^b

Step 2  y=100.3^log 0.8/log2

Step 3  y=100.3^1.9031/0.301

Step 4  y=100.3^-0.3219

Could anyone help me as to how i got the answer in step 4 from step3.Although I noe the answer given is correct..i tried solving it through log table but couldnt..require urgent help...