Answer:
the value of a would be one, i think
0.542=0.500 + 0.040+0.002
= 
=5 tenth + 4 hundredths + two thousandths
One tenth = 
One Hundredth= 
One thousandth= 
30x^7
Multiply the coefficients (6•5) to get 30, then add the exponents (4+3) to get 7
Hope this helps!
Wouldn't it be -1 (minus one)? 12 - 1 = 11 and 9 - 1 = 8.