4x - 8 = 16 what does X equal to?

To solve an equation for the value of a variable, undo the operations that are performed on that variable. The Order of Operations tells you the order they are performed. The operations can be undone in the reverse order by making use of inverse operations.

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Here, x is multiplied by 4 and -8 is added to the product. The opposite of -8 is +8, so we can add that to both sides of the equation to "undo" the addition.

4x -8 = 16 . . . . given

4x -8 +8 = 16 +8 . . . . add the opposite of the constant

4x = 24 . . . . . . . . . . simplify

To undo the multiplication, we multiply by the "multiplicative inverse" or "reciprocal" of the coefficient of x. Again, we do this to both sides of the equation.

(1/4)(4x) = (1/4)(24) . . . . multiply by inverse of 4

x = 6 . . . . . . simplify . . . . this is the value of x you are looking for

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Additional comment

This is called a "2-step" linear equation. The two steps are ...

isolate the variable term by adding the opposite of the constant
eliminate the variable coefficient by multiplying by its inverse

Note that multiplying by 1/4 is the same as dividing by 4. Adding the opposite of a number is the same as subtracting the number.

The properties of equality tell you that you can do anything you like to an equation, as long as you do the same thing to both sides of the equation. When solving equations, this is the one rule that you must never violate.