Algebra 1 Common Core Student Edition, Grade 8-9

I n C h a p te r 2 y o u le a r n e d h o w t o s o lv e e q u a t io n s i n o n e v a r ia b le. Y o u c a n a ls o s o lv e

e q u a tio n s b y u s in g a g r a p h in g c a lc u la t o r t o g r a p h e a c h s id e o f th e e q u a t io n as a

f u n c t io n r u le. T h e x - c o o r d in a t e o f t h e p o i n t w h e r e th e g r a p h s in t e r s e c t is t h e s o lu t io n

of the equation.

Ex a m p l e 2

q

Solve 7 = — jA: + 3 using a graphing calculator.

Step 1 P re ss ( ©. C le a r a n y e q u a tio n s. T h e n e n t e r e a c h s id e o f th e

given equation. For Y j =, enter 7. For Y 2 =, enter - |x + 3 by

pressing 3 4 fp QJJEQI 3. N otice that you

m u s t r e p la c e th e v a r ia b le k w i t h x.

Step 2 G r a p h t h e f u n c t i o n r u le s. U s e a s t a n d a r d g r a p h in g w in d o w b y

pressing 6. T h is g iv e s a w in d o w d e f in e d b y —10 ^ x ^ 10

and -10 ^ 10.

Step 3 Use the CALC feature. S elect INTERSECT and press

3 tim e s to fin d th e p o in t w h e re th e gra p h s in te rs e c t.

The calculator's value for the x-coordinate o f the p o in t o f intersection is

• 5 .3 3 3 3 3 3. T h e a c tu a l x - c o o r d in a t e is —5 |.

The solution o f the equation 7 = -^3 + 3 is - 531. |

Intersection

X= 5.333333 ;Y=7

r ........................................................................................................................................................................................................................................*\
Ex e r c i se s
Graph each function rule using a graphing calculator.

1. y=6x+3 2. y=-3x+8 3. y = 0.2x-7


2. y=-1.8x-6 5. y=-^x + 5 6. y = | x - 5


3. Open-Ended G r a p h y = -0 .4 x + 8. U s i n g t h e s c r e e n , e x p e r i m e n t w i t h
   values for Xmin, Xmax, Ymin, and Ymax until you can see the graph crossing
   both axes. W hat values did you use for Xmin, Xmax, Ymin, and Ymax?


4. R e a s o n i n g H o w c a n y o u g r a p h t h e e q u a t io n 2 x + 3y = 6 on a graphing
   calculator?

Use a graphing calculator to solve each equation.

9. 8 fl - 12 = 6 10. -4 = —3 t + 2 11. -5 = -0 .5 x - 2


10. 4 + |n = -7 13. |rf —1 = 6 14. -3 y -1 = 3.5

G

PowerAlgebra.com Concept Byte Graphing Functions and Solving Equations 261