How to use proportions for direct variation to solve for x

The video tutorial explains the concept of direct variation, where Y varies directly with X. It demonstrates how to solve for X when Y is given, using the principle that the ratio of Y to X is constant. The tutorial walks through setting up equations, equating ratios, and applying cross multiplication to find the solution. The process is illustrated with an example where Y is 4 when X is -2, and the task is to find X when Y is 6. The solution involves setting up the equation, applying cross multiplication, and solving for X, resulting in X being -3.

What does it mean when Y varies directly with X?

• Y is proportional to X with a constant

• Y is equal to X squared

• Y is always greater than X

• Y is inversely proportional to X

If Y is 4 when X is -2, what is the constant of variation?

• 1/2

• 2

• -1/2

• -2

How can two direct variations be equated?

• By subtracting their constants

• By setting their constants equal

• By adding their constants

• By dividing their constants

What is the first step in solving the equation using cross multiplication?

• Subtract the denominators

• Divide the numerators by the denominators

• Add the numerators

• Multiply the numerators with the opposite denominators

What is the value of X when Y is 6, given the direct variation?

• -3

• 3

• 6

• -6