Download 1.4 Write Equations and Inequalities

1.4 Write Equations and
Inequalities
Objective: Translate verbal
sentences into equations or
inequalities
Lingo
• Equation: a math sentence formed by
placing an = sign in between 2
expressions.
• Inequality: like an equation, but instead
of an = sign, it uses a <, >, ≤, or ≥.
Associated Words
Just like with addition, subtraction, multiplication, and
division, equations and inequalities also have
associated words.
=
<
>
≥
≤
Using Inequalities and Equations
• The difference of three times a number x and
2 is 5.
• The product of 3 and t is less than 12.
• The sum of 7 and twice a number t is at least
21.
Using Equations and Inequalities
• The sum of 42 and a number n is 51
• The product of 4 and a number w is at most
51
• The difference of a number t and 7 is greater
than 10 and less than 20.
Solutions
• A solution is what makes a statement true
• x + 3 = 5.
x = 2 is a solution.
Check: (2) + 3 = 5
5=5
Example
• Check whether 5 is a solution of the equation
or inequality.
• 24 – 3d = 9
• 3x + 4 = 18
• 2w – 7 ≤ 3
• 4 + 3p > 19
Review
• What does it mean for something to be a
solution?
• What are key words for
• <
• >
• ≤
• ≥
• Worksheet
Example 4 (in book)
• The last time you and 3 friends went to a
mountain bike park, you had a coupon for $10
off and paid $17 for 4 tickets. What is the
regular price for 4 tickets? Write a verbal
model before solving. If you pay the regular
price this time and share it equally, how much
does each person pay?
Example 4 continued…
• Suppose the price of 4 tickets with a half-off
coupon is $15. What is each person’s share if
you pay full price?
Example 5 (in book)
• A basketball player scored 351 points last year.
If the player plays 18 games this year, will an
average of 20 points per game be enough to
beat last year’s total? Write a verbal model to
represent the situation, then check for a
solution.
Example 5 continued
• Suppose the player plays 16 games. Would an
average of 22 points per game be enough to
beat last year’s total?
Write your own inequality or equation
statement
• Take out a sheet of scratch paper and write
two verbal inequality statements on one side
and what you believe to be their equivalent
inequality on the other side.
Homework
• Pg. 24-25: Worksheet + 6, 8, 10, 20-28
even, 40, 42, 46
Bonus 47,48