2-1 Writing and Interpreting Equations

Writing Equations

100

Twenty minus the quotient of 7 and x is the same as twice x

20 - 7/x = 2x

Example 1

200

Four times a number less 10 is equal to 16

4x-10=16

Check Example 1

300

What distinguishes an expression from an equation?

An equation contains an equal sign an expression does not

Think about it page 65

400

Question 1

3m + 2 = 18

500

Question 4

85-9y=7(4 + y)

Write an Equation

100

On Page 66 - Do Example 2

all 3 steps

Step 1 - are not

Step 2 - 799, 430, 193

Step 3 - (430 + 193) + n = 799

200

Etu has read 12 of the 32 chapters in his assigned book. He plans to finish the book by reading c chapters each day for 8 days until the book is due. Look at the check on page 66 and pick the best answer.

C - 12 + 8c = 32

300

Question 6

24 + 9h = 42

400

Question 8

3t + 39,000 = 216,000

500

Question 54

no, 

Writing an equation with Multiple Variables

100

Fill in the blanks on Example 3, page 67

all 4 steps

step 1 - perimeter, the length, and the width

step 2 - l=length w= width

step 3 - two times

step 4 - P = 2(l + w)

200

Translate into a formula: The horsepower of a motor is the product of the motor speed and the torque divided by 5252. Look at the check on page 67 and pick the best answer.

B) H = MT / 5252

300

Question 10

(p + t)-7 = 6

400

Question 12

4 (f + g) = 6g

500

Question 18

SA = 2 ( WH + LW + LH)

Write a sentence for an equation

100

Write a sentence for the equation

2z-1 = 5

two times z minus 1 equals 5

Example 4

200

Write a sentence for the equation

6z-15=45

A) Six times a number z minus fifteen equals forty-five

Check a on page 68

300

Write a sentence for the equation

(y+3)²=25

C) The quantity y plus 3 squared is 25

check b on page 68

400

Question 20

four times m is equal to fifty two

500

Question 22

Fifteen less than the square of r equals the sum of t and nineteen

Write a sentence for an equation with grouping symbols

100

Complete Example 5 on page 68

Three times the quantity y plus one equals twelve

200

Look at the check on page 69, pick the correct answers

A, C, E

300

Question 24

one third minus four fifths of z is four thirds of y cubed

400

Question 26

2 times the quantity t plus 4 times q is 2 times q plus 4 times t

500

Question 30

k squared minus n squared is twice b

Interpret an equation

100

In the surface area formula S = 2LW + 2LH + 2WH what does 2LW+ mean? and what does 2WH mean?

two times length times width plus

two times width times height

Example 6 first 2 boxes

200

finish the blanks for example 6 on page 69

rectangle, LW, back, left, sum of the areas of the faces

300

Do the check on page 70

Part A) A

Part B) A, B, E

400

Question 32

the volume equals pi times the radius squared times the height. the base is a circle so the expression represents the area of the base

500

question 36

distance equals rate times time. The expression rt represents the distance traveled by moving at a rate r for a time t