Evaluating Expressions and Formulas

Chapter 1.8

Review the order of operations

4

1. 4 – x for x = -8

1

4

8

-4

+ 4

Evaluating an Expression

(-8)substitute

multiply

add

simplify first

2 1

2 1

–

2a. 4x2 for x = -3

4

36

4

Evaluating an Expression

(-3)2substitute

exponents

multiply (9)

2b. (4x)2 for x = -3

(-12)2

144

(

Evaluating an Expression

[-3])2substitute

multiply

exponents

4

3. 2x2 – 3x for x = -2

2

8

2

14

+ 6

Evaluating an Expression

substitute

exponents

multiply

(-2)2 – 3 (-2)

add

(4) – 3(-2)

6

4. 6a + 4ab2 – 5 for a = , b = 3

6

-12

Evaluating an Expression

( ) + 4( )(3)2 – 5substitute

exponents

multiply

simplify first

change to adding

1

6 -1

6 -1

6 -1

1( ) + 4( )(9) – 56

-1 6

-1 2

3

3

1

-1 + (-6) + (-5)

add

5. Find the of a triangle with an of and a of .

212

A =

m2 10 m2or

Evaluating a Formula

A = 2 1

2 1 (3 m)

formula

substitute

multiply

ab

area altitude base

(7 m)

3 meters 7 meters

10.5 m2or

A =

6. Find the of a circle if the is .

A =

Evaluating a Formula

A =

(3.14)

formula

substitute

exponents

πr2

area radius

(3 m)2

3 meters

A = (3.14)(9 m2)multiply

28.26 m2A =

7. What is the Celsius temperature when the Fahrenheit temperature is F = 68°?

C =

Evaluating a Formula

C = 9 5

9 5 (68°

formula

substitute

subtract

(F – 32°)

– 32°)

C = 9 5 (36°)

multiply

simplify first

4°

1

C = 20°

8. On a Canadian highway the minimum speed is 65 km/hr. A truck is travelling at 35 m/hr. Is it violating the minimum speed limit?

k =

Evaluating a Formula

k ≈ 1.61r (1.61)

formula

substitute

multiply(35)

k = 56.35 km/hr

The truck is travelling below the speed limit.

It is violating the law.

Evaluating Expressions and Formulas

Chapter 1.8