Warm Up #4. HW Check – Inverse Worksheet 2.3 - Direct Variation.
-
Upload
logan-perry -
Category
Documents
-
view
228 -
download
0
Transcript of Warm Up #4. HW Check – Inverse Worksheet 2.3 - Direct Variation.
Warm Up #4
HW Check – Inverse Worksheet
2.3 - Direct Variation
Direct Variation
A linear function defined by an equation of the form y = kx, where k ≠ 0, represents direct variation.
Constant of Variation
The Slope, k, is constant.
It can be represented at the ratio of
Identifying Direct Variation from a Table
Determine whether y varies directly with x. If so, find the constant of variation and write the equations. 1. 2. X Y
2 8
3 12
5 20
X Y
1 4
2 7
5 16
You Try!!
Determine whether y varies directly with x. If so, find the constant of variation and write the equations. 1. 2. X Y
-1 -2
3 4
6 7
X Y
-6 -2
3 1
12 4
Identifying Direct Variation from an Equation
For each function, determine whether y varies directly with x. If so, find the constant of variation:1. y = 4x
2. 2y = 3x
3. y = 2x + 3
You Try!!
Determine whether y varies directly with x. If so, find the constant of variation. 1. y = x/2
2. 2y – 1 = x
3. 4x = 8y
4. 7x + 4y = 10
Using Proportions
If we know that y varies directly with x. We can use proportions to find missing information.
Ex. Suppose y varies directly with x, and x = 3 when y = 7. Find x when y = 21.
y1x1
y2x2
You Try! y varies directly with x:
If y = 25 when x = 15, find x when y = 10
If y = 30 when x = -3, find y when x = -9
Writing Equations
Write an equation of the direct variation that includes the point (10, -15).
You Try: Write an equation of the direct variation that includes the point (-40, 16).
Word Problems
The Height of an object varies directly with the length of its shadow. A person 6 ft tall casts an 8.5 ft shadow, while a tree casts a 38 ft shadow. How tall is the tree?
Word Problem
The amount of a persons paycheck p varies directly with the numbers of hours worked t. For 4o hours of work, the paycheck is $390. Write an equation for the relationship between hours worked and pay.
Class work – Group Work
Direct Variation Worksheet
Turn in when you are done!
Homework
Mid-Chapter Review Sheet
# 4 – 15 Show all work for credit!!