Most of the properties of equality also apply to inequalities. The exception is multiplication (or division) by a negative number. An equation can be multiplied or divided by any number you like (except division by 0) and it will remain true. <em>An inequality must have the relation symbol reversed when multiplying or dividing by a negative number</em>.
Here, we don't run into that issue, because we can solve this by dividing both sides by the coefficient of x, which is +3.
