1-6 Writing Expression 1-6 Writing Expression (pgs 29-(pgs 29-32)32)

1-9 Using formulas 1-9 Using formulas (pgs 40-43)(pgs 40-43)

9P3:Describe problems using symbolic representation9P3:Describe problems using symbolic representation

What is the difference between an equation and an What is the difference between an equation and an expression???expression???

ExpressionsExpressions combination of variables, numbers, and operations. combination of variables, numbers, and operations. can be can be simplifiedsimplified by combining like terms by combining like terms (ex: 2xy + 4x +3 or 2a + 3a)(ex: 2xy + 4x +3 or 2a + 3a)

EquationsEquations two expressions that are two expressions that are equalequal. . Both sides have the same value. Both sides have the same value. Can be Can be solvedsolved to find the value that works( most to find the value that works( most

equations only have one number that makes them equations only have one number that makes them true.true.

(ex: 2x +3 = 4x +5) (ex: 2x +3 = 4x +5) ← x= -1 no other number works← x= -1 no other number works

Things to note:Things to note: Watch subtraction problems: x - 2 is Watch subtraction problems: x - 2 is

different than 2 – xdifferent than 2 – x

Remember your vocabulary… (What words Remember your vocabulary… (What words mean + - mean + - ×× ÷)÷)

Put the equal sign in the equation where Put the equal sign in the equation where you see the word is (or other forms such as you see the word is (or other forms such as has, had, was, were, etc.. )has, had, was, were, etc.. )

Which words/symbols mean + - Which words/symbols mean + - ×× ÷÷

++ -- ×× ÷÷plus plus

and and

added toadded to    

greater than greater than

more thanmore than increased byincreased by

total total

SumSum

++

minus minus difference difference

from from

less less

less than less than fewer thanfewer than

decreased by decreased by

take awaytake away

--

times times product product

at at

double, double, triple, etc. triple, etc.

twice twice of of (fractions &%)(fractions &%)

× • ( ) × • ( ) abab

quotient of quotient of

goes intogoes into

perper

divided bydivided by

÷ ÷ aa aa//bb

bb

Write an expression for the followingWrite an expression for the following1) The sum of a number and 31) The sum of a number and 3

n + 3n + 3

2) three less than twice a number2) three less than twice a number

2n - 32n - 3

3) 2 times the sum of 8 and a number3) 2 times the sum of 8 and a number

2(n+8)2(n+8)

4) Let s be Sue’s age. If Sue is 10 years older than Roy, write 4) Let s be Sue’s age. If Sue is 10 years older than Roy, write an expression for Roy’s agean expression for Roy’s age

s - 10s - 10

Use formula to solve problemsUse formula to solve problems The speed of an airplane (a) is the Mach number The speed of an airplane (a) is the Mach number

(M) times the speed of sound (s).(M) times the speed of sound (s).

What equation represents this relationship?What equation represents this relationship?

a=Msa=Ms

If an airplane is traveling at Mach 1.5 and the If an airplane is traveling at Mach 1.5 and the speed of sound is 720mi/hr, what is the speed of speed of sound is 720mi/hr, what is the speed of the airplane?the airplane?

Step 1: write formula a =Ms Step 1: write formula a =Ms

Step 2: Substitute a =1.5*720mi/hrStep 2: Substitute a =1.5*720mi/hr

Step 3: simplify/label units a = 1080 mi/hrStep 3: simplify/label units a = 1080 mi/hr

AssignmentAssignment

1-6/30/ 2-48eoe, 62-72 e1-6/30/ 2-48eoe, 62-72 e 1-9/42-43/ 2-22e, 26-34e1-9/42-43/ 2-22e, 26-34e

Marker board Marker board Pg 30Pg 3033232325253131393943434545676771 71 Pg 42Pg 4233131317172727