1. Expressions With Substitution
King/Halling
Algebra

2. AIM
When we want to evaluate expressions using specific values, how can we replace variables with the numbers they equal? Topic: Expressions & Substitution

3. DO NOW
Take out your completed foldable and your worksheets from yesterday. Make sure you know what homework you are missing when we come around to check these assignments.
Complete the following using PEMDAS FLTR:
[10(6 – 4)2 – (16 ÷ 4)] + 52

4. [10(6 – 4)2 – (16 ÷ 4)] + 52

5. Evaluating Expressions
When evaluating expressions, sometimes you will find that they include variables
Example: 10(a – 3) x (b + 4)
Often times they will ask you to evaluate these expressions using given values for these variables. Let’s try it!!

6. 10(a – 3) x (b + 4) Evaluate this expression when a = 4 and b = 6.
In order to complete this, we simply substitute the values of the variables into the expression
SO… 10(a – 3) x (b + 4)  10(4 – 3) x (6 + 4)
Now solve it!  10(1) x (6 + 4)
10(1) x (10)
10 x 10
100

7. 10(a – 3) x (b + 4)
The answer will change when we change the value of the variables we try.
Let’s use a = 6 and b = 4
10(a – 3) x (b + 4)  10(6 – 3) x (4 + 4)
10(3) x (4 + 4)
10(3) x (8)
30 x 8
240

8. Evaluate 6(7 – x)2 + y for x=4 and y=9
Evaluate 2(m + 9) – 52 x n for m=12 and n=4
Evaluate [7(5 – a) + b2 ÷ c for a=4,b=9,& c=4

9. Using the Calculator
To check your answers or complete these problems in a different way, you can use your calculator
The Store function of the calculator is one of the most useful buttons when taking the Regents

10. Steps for the Calculator
Type the value of the variable into the calculator
Hit the STO> button directly above ON
Hit ALPHA and the variable you want to use
Type in the problem and hit ENTER

11. Solve the equation using substitution to check your answer!
11(a – 3) ÷ b2 when a=11 and b = 2
Hit 9 then STO> and ALPHA “A”
Hit 2 then STO> and ALPHA “B”
Type in the equation 11(A – 3) ÷ B2
Hit ENTER
The answer is 22
Solve the equation using substitution to check your answer!

12. Example 2: Evaluate [10(a + 3) – b2] when a=5 and b=4

13. Example 3: Evaluate [33 – 10(x – 1)]y when x=4 and y=2

14. More Practice Evaluate 6(7 – x)2 + y for x=4 and y=9
Evaluate 2(m + 9) – 52 x n for m=12 and n=4

15. Exit Ticket
Evaluate the following expressions using whatever method you prefer and the values provided for the variables:
(a2 + b2) – 10 when a=6 and b=7
a2 + (b2 – 10) when a=6 and b=7