# Algebra II Chapter 2 Section 3 Direct that Variation.

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Algebra II Chapter 2 Section 3 Direct that Variation

Direct variation A special type of linear function where X and Y intercepts are 0

Tests for Direct Variation As a table: the ratio of range over domain remains constant As a graph: line goes through (0,0) As an equation: all constant terms can be eliminated

Table XY 28 312 520 8/2 = 4 12/3 = 4 20/5 = 4 4 is called the constant of variation

Equation Y = 3X Y + 6 = 2 ( X + 3)

Direct Variation Given one point you can find the equation of a direct variation Find equation of a direct variation that goes through point (4,5)

Find the Constant of variation Constant of variation = k = Y 1 / X 1 K = 5/4

Put it into the direct variation form Y = kX Y = 5/4 X

U Try Find the equation of the following direct variations 1. Goes through (-3,8) 2. Has a k of 6 3. Goes through (-2,-4)