Warm-UpThe table below shows the number of juniors enrolled in Algebra 2 at LHS in six of the last 7 years. The number for the third year has been misplaced. Estimate the number of students enrolled in Algebra 2 in the third year. year 1 2 4 5 6 7

# 33 29 45 43 43 61

7 minutes

Correlation and Prediction

x

y

x

y

perfect negative

correlation

perfect positive

correlation

x

y

no reliable correlation

r = -1 r = 0 r = 1

1.6 Intro to Solving Equations1.6 Intro to Solving Equations1.6 Intro to Solving Equations1.6 Intro to Solving EquationsObjectives: •Write and solve a linear equation in one variable•Solve a literal equation for a specified variable

Properties of EqualityReflexive a = aSymmetric If a = b, then b = a.Transitive If a = b and b = c, then a = c.Addition If a = b, then a + c = b + c.Subtraction If a = b, then a – c = b – c.Multiplication If a = b, then ac = bc.

Division If a = b, then ,

where c 0.

=a

c

b

c

Example 1The relationship between the Celsius

temperature, C, and the Fahrenheit

temperature, F, is given by .9

F C 325

Find the Celsius temperature that is equivalent to 1220F.

9F C 32

5

9122 C 32

5

990 C

5

50 C

500C

Example 2Solve.

3x – 8 = 5x - 20-3x -3x

-8 = 2x - 20+ 20 + 2012 = 2x

2 2

CHECK:

6 = x

3x – 8 = 5x - 20

3(6) – 8 = 5(6) - 2018 – 8 = 30 -

20 10 = 10

Example 3Selene rented a car for one day. The rate was $30 per day plus $0.20 per mile. She paid a total of $84. How many miles did she drive?

0.2x + 30 = 84

0.2x = 54x = 270

x = number of miles that Selene drove

Example 4Solve 5.02x – 3.02 = -1.76x + 8.75 by graphing.

y = 5.02x – 3.02

1) Rewrite as a pair of equations

y = -1.76x + 8.75

2) Graph the two equations on the same screen3) Find the point of intersection

Example 5

P(1 + ni) = A Multiply by (1+ ni).

P + Pni = A distributive property

Pni = A – P Subtract P.

Divide by Pi.n =

A – P

Pi

Solve P = for n.

A

1+ ni

Homework

p.40 #22p.49 #13,23,31,35,37,41,43,47,51,53,59,69