1. Algebra 1
Section 2.2

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3. Evaluating an Expression
Substitute the given values for the variables.
Evaluate by following the order of operations.

4. Example 1 Evaluate 3a2 - b + c3 when a = 1, b = 4, and c = 3.
3(1) 26

5. Example 2 Evaluate x2yz2 when x = -½, y = -2, and z = ¼. 1 4 -2 16 • •-1 1 4 -2 16
• •
x2yz2
(-½)2(-2)(¼)2 2 1 32 -

6. Definition
A formula is an equation that expresses the relationship between related quantities. 9 5
F = C + 32
p = 0.433h

7. Definition
Formulas are mathematical sentences that are used extensively in many professions.

8. Math Verbs =  ≈   is, equals is not equal to
is approximately equal to
is a subset of
is an element of

9. Math Verbs  > < is not an element of is greater than
is less than
is at least
is at most

10. Perimeter and Area Formulas
Rectangle
p = 2l + 2w
A = lw
Square
p = 4s
A = s2

11. Perimeter and Area Formulas
Circle
c = 2r
A = r 2
Triangle
p = a + b + c
A = ½bh

12. Example 3
Find the perimeter of a rectangle whose length is 8 cm and whose width is 3 cm.
p = 2l + 2w
p = 2(8) + 2(3)
p =
p = 22 cm

13. Example 4 Find the area of a circle with a radius of 9 ft. A =  r 2
A = ft2

14. Using Formulas Write the correct formula.
Substitute the given values for the variables in the formula.
Evaluate the expression.

15. Homework: pp