8 - 3x = 128

Subtract 8 from both sides.

-3x = 120

x = 120/-3

x = -40

Can someone explain this to me?? I don't understand why you would subtract 8 and not add 8... also, why did the 3 suddenly become a negative? HELP ;D

Because on the left side, 8 is already positive and you want to get rid if it. You would then subtract 8 on both sides. -3x was already negative . Hope I helped !

thank you so much! I get it now! ;)

Of course! I'd be happy to explain.

In the equation 8 - 3x = 128, the goal is to isolate the variable x on one side of the equation.

To do this, we need to perform operations to manipulate the equation. The first step is to get rid of the constant term 8, so we can directly work with the variable term -3x.

To eliminate the 8, we can subtract it from both sides of the equation, which maintains the equality. This step gives us:

8 - 8 - 3x = 128 - 8

By subtracting 8 from both sides, we cancel out the 8 on the left side, leaving only the variable term -3x:

-3x = 120

Now, let's address your confusion about the negative sign attached to the 3. The negative sign was already present in the original equation 8 - 3x = 128. It represents the coefficient of the variable x, which in this case is -3. This negative sign was carried over to the next step when we subtracted 8 from both sides, resulting in -3x = 120.

Finally, to solve for x, we divide both sides of the equation by -3. Dividing by -3 is equivalent to multiplying by -1/3. This gives us:

x = 120 / -3

Simplifying the division, we get:

x = -40

So, the solution to the equation is x = -40.

Remember, when solving an equation, it's important to perform the same operation on both sides in order to maintain equality.