Name ______________________________ Date___________ #7 Chapter #____5_____Assignment Section #___5.2______Page Number___301‐306_____ Section Title: Direct Variation
Assignment: Pg 304 #9-23 odd, 27-33 odd, 52, 54 Notes Complete Assignment Complete Teacher Signature/Date:
____________________
Target Goal: The students will be able to: 
write and graph an equation of a direct variation.
OPENER: Look back through your notes, if you need, to fill in the blanks below. 1. Write out the formula to find the slope of a line given 2 points.____________________ 2. Write out the slope‐intercept form for the equation of a line._____________________ 3. Write out the point‐slope form for the equation of a line:________________________ 4. Write out the standard form for an equation of a line:_______________________ a. What are its conditions for standard form? i. ________________________________________ ii. ________________________________________ iii. ________________________________________ 5. Write the equation of a horizontal line which passes through the point (‐2, 11)._______ 6. Write the equation of a vertical line which passes through the point (‐2, 11)._________ 7. Write the equation in standard form: y – 5 = ‐2(x + 6) ____________________ 3
8. Write the equation in standard form: y + 7 = (x – 12) ____________________ 4
Notes #7 D: Direct Variation A relationship that can be represented by a function in the form y=kx where k is not equal to 0. D: Constant of Variation K is the constant of variation and is also the coefficient of x. y
x
It is also the ratio of y to x. (Solve y = kx for k to get k = .) The graph of a direct variation is linear (it’s a line!) _____________________________________________________________________________ 1‐6 Solve each of the following for y to see if the equation represents a direct variation. If so, find the constant of variation (K). 2
Ex 3) 4y + 3x = 7 Ex 1) 8y = 3x Ex 2) y  x 5
Ex 4) 4x + 5y = 0 Ex 5) ‐5 + 6x – 5 = 4y Ex 6) ‐18x = 3y‐ 25 _____________________________________________________________________________ 7‐9 Suppose y varies directly with x. Use the given information to find “K”. Then write a direct variation equation that relates x and y. Finally, find y when x = 15. Ex 7) y = ‐10, x = 2 Ex 8) y = 10.4, x = 4 Ex 9) y = 125, x = ‐5 Ex 10) Suppose y varies directly with x, and y = 35 when x = 5.  Find k.  What direct variation equation relates x and y?  Find the value of y when x = 9. _____________________________________________________________________________ Ex 11) Suppose y varies directly with x, and y = 12 when x = ‐2.  Find k.  What direct variation equation relates x and y?  Find the value of y when x = 13. _____________________________________________________________________________ 12‐14 Graph each direct variation equation. Be sure to name 2 points on each line and use a straight edge. 2
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Ex 12) y = 4x Ex 13) y =  x Ex 14) x = y 3
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ASSIGNMENT‐‐#7 Pg 304 #9-23 odd, 2733 odd, 52, 54
When you are done with assignment #7 and you have gone on line to grade the
assignment, with a RED pen, assess your learning!!
Target Goal: The students will be able to:
 write and graph an equation of a direct variation.
Get it _________Needs more Practice________Need extra help_______