Is this your equation?: 4.5x - 7 = 20 _____________________________________________________________
Your goal is to isolate x. By isolating the x-variable, you effectively receive the answer. In order to isolate x, you move the -7 term [Note: that the sign in front of a number signifies if it's positive or negative] as well as 4.5 behind the equality symbol. To do this, you do reverse operations to both sides. Start with -7.
The opposite of negative 7 is positive 7, therefore -7 + 7 = 20 + 7 -7 + 7 cancels each other out and 27 takes the place of 20. We now have: 4.5x = 27
Since you have to multiply 4.5 by x originally, you have to divide now. Divide 4.5 by itself and 27 by 4.5. This gives you 1 and 6. [Note that a 1 in front of a variable is like saying only that variable]
(1)x = 6, Therefore x is equivalent to 6.
Briefly check your work by taking the original equation and substituting x with 6. If 4.5(6) - 7 equals 20, 6 is our right answer. [Note: Solve with PEMDAS]
