Solving a proportion using cross multiplication

The video tutorial covers solving proportions using cross multiplication. It begins with an introduction to proportions and explains the process of cross multiplication. The tutorial then demonstrates the application of the distributive property in solving equations and discusses the handling of negative signs. The video concludes with the final solution to the problem, emphasizing that the placement of negative signs does not affect the outcome as long as they are applied consistently.

What happens to the negative sign when solving equations involving proportions?

Describe the process of reducing fractions when solving for X in the equation 21X = 15.