What Should Be Done in Order to Isolate the Variable

What should be done in order to isolate the variable x on one side of an equation and the numbers on the other?

A) Carry out the opposite of the operation that appears on the same side of the equal sign as x.
B) Cross multiply all the numbers on the same side of the equal sign as x.
C) Divide by 100 the numbers located on the same side of the equal sign as x.
D) Identify the common denominator of the numbers on the opposite side of the equal sign from x.