Download notes 1-1 & 1-2 - Evaluating and Writing Algebraic Expressions

You will evaluate algebraic expressions, an translate between algebraic expressions and word phrases.
Evaluating and Writing Algebraic Expressions
Notes 1-1 & 1-2
Expression – a mathematical phrase that contains numbers, ______________ (add,
divide, etc…), and/or variables
expressions contain NO _____________ - that makes it an ____________
Variable – a letter that represents a value that can __________
Coefficient – a ___________ multiplied by the variable
comes in front of the variable
Algebraic Expression – a phrase with one or more variables
Constant – a number that does not change (not attached to a variable)
8𝑥 − 3
To evaluate an algebraic expression, you substitute in a value for the variable and simplify
using the Order of Operations.
Order of Operations – a rule which tells us the _________ in which to perform the steps
of an expression
P
E
M/D
A/S
Example 1 – Evaluate each expression for the given value of the variable.
a) x + 5 for x = 11
b) 2a + 3 for a = 4
c) 4(3 + n) – 2 for n = 0, 1, & 2
Example 2 – Evaluate each expression for the given values of the variables.
a) 5x + 2y for x = 13 and y = 11
b) 2.5p – 4 q for p = 12 and q = 6.5
Example 3 – If c is a temperature in degrees Celsius, then 1.8c + 32 can be used to find
the temperature in degrees Fahrenheit. Convert each temperature from degrees Celsius
to degrees Fahrenheit.
a) freezing point of water: 0oC
b) highest recorded temperature in US:
57oC
Operation
+
−
×
÷
Translating Between Words and Math Symbols
Expression
Word Phrases
add 5 to a number
the sum of a number and 5
𝑛 + 5
5 more than a number
a number increased by 5
subtract 11 from a number
the difference of a number and 11
𝑥 − 11
*11 less than a number*
a number decreased by 11
3 multiplied by a number
3𝑚 or 3 ∙ 𝑚 or 3(𝑚)
the product of 3 and a number
𝑎
7 divided by a number
or 𝑎 ÷ 7
7
the quotient of a number and 7
Example 1 – Write an algebraic expression for each word phrase.
a) 1 more than the product of 12 and p
b) 4 less than n divided by 2
Example 2 – Write a word phrase for the algebraic expression.
a) 4 – 7b
b) 5 + 7n
Example 3 – A company aired its 30-second commercial n times during the Super Bowl at a
cost of $2.4 million each time. Write an algebraic expression to evaluate what the cost
would be if the commercial had aired 2, 3, or 4 times.