| Objective(s):
By the end of this lesson the student will be able to: translate
a word sentence into a mathematical expression. |
Pre-Class
Assignment: Completion of Basic
Algebra - Lesson 1
Resources/Equipment/Time Required:
Outline:
In the first
lesson, you learned that numbers and variables form sentences, or algebraic
"expressions." When you take information from a sentence and turn it into
a mathematical expression, it is called "translating."
A place to
begin:
-
When you write
algebraic expressions, use +, -, and = signs. For division, use / , the
same way you know that when you see a fraction, it means to divide the
top number by the bottom number.
-
For multiplication,
write the expression with no symbol or sign between them as the X (multiplication)
symbol can be confused with the variable x. For example 3 times the variable
y should be written 3y. You can also use parentheses to indicate multiplication.
This is especially useful in longer problems such as (3y)(4-2x).
-
When you want
to multiply something AFTER another expression has been done first, use
parenthesis. For example, if you want to add x and y and THEN multiply
the result by 7, write it this way: 7(x + y).
-
To translate from
language to a math expression, read the sentence carefully. Then decide
what operations it will take to reach a solution. Write this into an algebraic
expression.
Let's Get Started:
Here is the
word problem:
I am stocking
shelves at a T-shirt store. I have been given eight boxes of T-shirts.
There are 25 T-shirts in each box. My instructions are to take one T-shirt
from every box and set it aside to be given to the poor. How many T-shirts
will be left for me to put on the store shelves after I sort out the T-shirts
to be given to the poor?
Here is the
algebraic expression:
8(25-1)
8(24)
192
If you don't
know the number of T-shirts in each box, then substitute the variable x
for that. Then the expression would look like this:
8(x - 1)
Now it's time
for you to try a few.
Assignment(s)
including Answer key:
EXERCISE:
-
Katie is 21 years
old. Write an algebraic expression that tells how old she will be in five
years. Let x represent that age. Solve from your expression.
-
One hamburger
costs x cents. Write an algebraic expression that tells how much 4 hamburgers
will cost.
-
Sandy is 21 years
old. Al is five years older. How old will Al be in five years? Let x represent
Al's age in five years. Solve for x.
-
I have ten hats
that cost $47.50 for all of them. Write an algebraic expression to show
how much one of those hats cost, letting y represent the answer. Solve
for y.
-
I have ten hats
that cost $47.50 for all of them. How much will I have to sell EACH hat
for to make a profit of $1 on each? Set it up in an algebraic expression
to solve.
ANSWER KEY Click
Here:
Pre-Requisite
To: Basic
Algebra - Lesson
3 Solving for X
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