Chapter 1 Review College Algebra

Remember the phrase “Please Excuse My Dear Aunt Sally” or PEMDAS. ORDER OF OPERATIONS 1. Parentheses - ( ) or [ ] 2. Exponents or Powers 3. Multiply and Divide (from left to right) 4. Add and Subtract (from left to right)

Evaluate Is your answer 33 or 19? You can get 2 different answers depending on which operation you did first. We want everyone to get the same answer so we must follow the order of operations.

Once again, evaluate  3 and use the order of operations. = (Multiply.) = 19 (Add.)

Example #1 14 ÷ = (Divide l/r.) = (Multiply.) = 1(Subtract.)

Example #2 3(3 + 7) 2 ÷ 5 = 3(10) 2 ÷ 5(parentheses) = 3(100) ÷ 5(exponents) = 300 ÷ 5(multiplication) = 60(division)

Example # (6 + 1) 4 = (7) 4(parentheses) = (7) 4(exponents) = (7) 4 (Multiply l/r.) = (Multiply l/r.) = (Subtract l/r.) = (Add l/r.) = 130(Add.)

Which of the following represents · 5 in simplified form? 1. -3, ,996 Answer Now

Simplify (10 - 3) Answer Now

Simplify 24 – 6 · 4 ÷ 2 Answer Now

1.substitute the given numbers for each variable. 2.use order of operations to solve. Evaluating a Variable Expression To evaluate a variable expression:

Example # 4 n + (13 - n)  5 for n = 8 = 8 + (13 - 8)  5 (Substitute.) =  5 (parentheses) = (Divide l/r.) = 9 (Add l/r.)

Example # 5 8y - 3x 2 + 2n for x = 5, y = 2, n =3 = 8    3 (Substitute.) = 8    3 (exponents) =   3 (Multiply l/r.) =  3 (Multiply l/r.) = (Multiply l/r.) = (Subtract l/r.) = -53 (Add l/r.)

What is the value of -10 – 4x if x = -13? Answer Now

What is the value of 5k 3 if k = -4? Answer Now

What is the value of if n = -8, m = 4, and t = 2 ? Answer Now

An expression is NOT an equation because it DOES NOT have an equal sign. There are 2 types of expressions Numerical 3x 3x + 10 Algebraic Notice there are no equal signs in these expressions so they are not equations !

A numerical expression contains only numbers and symbols and NO LETTERS. 5 times 3 plus 8 (53) + 8

An algebraic expression contains only numbers, symbols, and variables. It is sometimes referred to as a variable expression. The product of 3 and x 3x The sum of m and 8 m + 8 The difference of r and 2 r - 2

What is a variable? A variable represents an unknown value. 1) 4 + x 2) 10 – ? 3) 5y 4) 20 A variable can be any letter of the alphabet since it represents an unknown.

Word Phrases for multiplication are: The product of 5 and a number c Seven times a number t 6 multiplied by a number d 5 c or 5c 7 t or 7t 6 d or 6d

The Placement rule for multiplication is: The product of 5 and a number c Seven times a number t 6 multiplied by a number d 5 c or 5c 7 t or 7t 6 d or 6d Always write the variable AFTER the number.

Evaluate means to find the value of an algebraic expression by substituting numbers in for variables. m = m ?

Evaluate means to find the value of an algebraic expression by substituting numbers in for variables. r = r ?

Evaluate the variable expression when n = 6. 1)2) Evaluate just means solve by substitution.

Evaluate the variable expression when n = 6. Evaluate just means solve by substitution. 3) 4)

Evaluate the algebraic expression when n = 8. 1)2)

Evaluate the expression if a = 3 and b = 4. 1)2)

Evaluate the expression if a = 3 and b = 4. 3)4)

Evaluate the expression if x = 5 and y = 3. 1) 2)

#2 Show the substitution. Show your work down. Circle your answer. Show your work one step at a time down. No equal signs! Evaluate means solve. Evaluate i f x = 3 and y = 4

Combining Like Terms  In algebra we often get very long expressions, which we need to make simpler. Simpler expressions are easier to solve!  To simplify an expression we collect like terms. Like terms include letters that are the same and numbers.

Let ’ s try one…  Step One: Write the expression. 4x + 5x x + 7  Collect all the terms together which are alike. Remember that each term comes with an operation (+,- ) which goes before it. 4x, 5x, and -2x -2 and 7  Simplify the variable terms. 4x+5x-2x = 9x-2x = 7x  Simplify the constant (number) terms = 5  You have a simplified expression by writing all of the results from simplifying. 7x + 5

Another example…  10x – 4y + 3x 2 + 2x – 2y 3x 2 10x, 2x -4y – 2y  3x x – 6y Remember you cannot combine terms with the same variable but different exponents.

Now you try… Simplify the following:  5x + 3y - 6x + 4y + 3z  3b - 3a - 5c + 4b  4ab – 2a 2 b + 5 – ab + ab 2 + 2a 2 b + 4  5xy – 2yx + 7y + 3x – 4xy + 2x A A A A

You Try #1  Simplify the following: 1. 5x + 3y - 6x + 4y + 3z 5x, -6x 3y, 4y 3z -x + 7y + 3z

You Try #2  Simplify the following: 2. 3b - 3a - 5c + 4b 3b, 4b -3a -5c -3a + 7b – 5c

You Try #3  Simplify the following: 3. 4ab – 2a 2 b + 5 – ab + ab 2 + 2a 2 b + 4 4ab, -ab -2a 2 b, 2a 2 b 5, 4 ab 2 3ab + ab 2 + 9

You Try #4  Simplify the following: 4. 5xy – 2yx + 7y + 3x – 4xy + 2x 5xy, -2yx, -4xy 7y 3x, 2x -xy + 7y + 5x

by Mr. Fitzgerald

Five Properties 1.Distributive 2.Commutative 1.“order doesn’t matter” 3.Associative 1.“grouping doesn’t matter” 4.Identity properties of one and zero 5.Inverse “opposite”

(2 + 1) + 4 = 2 + (1 + 4) Associative Property of Addition 1.

3 + 7 = Commutative Property of Addition 2.

8 + 0 = 8 Identity Property of Addition 3.

6 4 = 4 6 Commutative Property of Multiplication 5.

17 + (-17) = 0 Inverse Property of Addition 6.

2(5) = 5(2) Commutative Property of Multiplication 7.

3(2 + 5) = Distributive Property 9.

6(78) = (67)8 Associative Property of Multiplication 10.

5 1 = 5 Identity Property of Multiplication 11.

(6 – 3)4 = 64 – 34 Distributive Property 13.

1(-9) = -9 Identity Property of Multiplication 14.

3 + (-3) = 0 Inverse Property of Addition 15.

1 + [-9 + 3] = [1 + (-9)] + 3 Associative Property of Addition 16.

-3(6) = 6(-3) Commutative Property of Multiplication 17.

= -8 Identity Property of Addition 18.

37 – 34 = 3(7 – 4) Distributive Property 19.

6 + [(3 + (-2)] = (6 + 3) + (- 2) Associative Property of Addition 20.

7 + (-5) = Commutative Property of Addition 21.

(5 + 4)9 = Distributive Property 22.

-3(5 4) = (-3 5)4 Associative Property of Multiplication 23.

-8(4) = 4(-8) Commutative Property of Multiplication 24.

5 1 / = 5 1 / 7 Identity Property of Addition 25.

3 / 4 – 6 / 7 = – 6 / / 4 Commutative Property of Addition 26.

1 2 / 5 1 = 1 2 / 5 Identity Property of Multiplication 27.

-8 2 / = -8 2 / 5 Identity Property of Addition 29.

[(- 2 / 3 )(5)]9 = - 2 / 3 [(5)(9)] Associative Property of Multiplication 30.

6(3 – 2n) = 18 – 12n Distributive Property 31.

2x + 3 = 3 + 2x Commutative Property of Addition 32.

ab = ba Commutative Property of Multiplication 33.

a + 0 = a Identity Property of Addition 34.

a(bc) = (ab)c Associative Property of Multiplication 35.

a1 = a Identity Property of Multiplication 36.

a +b = b + a Commutative Property of Addition 37.

a(b + c) = ab + ac Distributive Property 38.

a + (b + c) = (a +b) + c Associative Property of Addition 39.

a + (-a) = 0 Inverse Property of Addition 40.