Which are the possible first steps in solving the equation 4^x+3=18

According to the rule of BODMAS multiplication goes first.

B - brackets
O - operations
D - division
M - multiplication
A - addition
S - subtraction

to answer the question, 4 ^ x goes first. which equals 4x. the new equation would be:
4x + 3 = 18
now you have to move +3 over the equals sign which becomes negative (-):
4x = 18 - 3
4x = 15
next you have to get the x to be alone, move the 4 over the equals sign. 15 is now divided by 4:
x = 15/4
x = 3.75