Add 2x to both sides,
3x+9=18
Subtract 9 from both sides. 3x=9
Divide both sides by 3.
x=3
The Scientific notation for above value is :

Sorry I only know the answer to b.
The all time high temperature is 92 in June
The all time low temperature is -38 in February.
I believe the answer is (x+3)x(x-1) hope this helps