Page 26 - Math Course 1 (Book 2)

Evaluating Expressions

MO. 7 - L4b one half of the product of length of
Words base and height
Order of Operations:

Algebraic Expressions Variables b = base; h = height

1
Let’s Begin Equation 2 x b • h

1
Answer bh
Evaluate an Algebraic Expression 2

Example

2
2
Evaluate 2(x – y) + z if x = 4, y = 3, and z = 2. B. Find the area of one side of the Great Pyramid.
1
Replace x with Evaluate bh for b = 230 and h = 187
2
2
2
2
2(x – y) +z = 2(4 – 3) + 2 2 4, y with 3 and z
with 2. Replace b with 230
1
1
bh = (230 • 187) and h with 187.
2
= 2(16 – 3) + 2 2 Evaluate 4 . 2 2
Subtract 3 from 1 Multiply 230 by
= 2(13) + 2 2 = (43,010)
16. 2 187.
2
= 2(13) + 4 Evaluate 2 . Multiply by
1
= 43,010 2
2 43,010.
= 26 + 4 Multiply 2 and 13.
= 30 Add. = 21, 505 Divide 43,010 by 2.

Answer 30 Answer The area of one side of the
2
Great Pyramid is 21,505 m .

Real World Example Your Turn!

ARCHITECTURE Evaluate an Algebraic Expression
Each side of the Great Pyramid at Giza, Egypt, is a Evaluate x ³ – y + z, if x = 3, y = 2, and z = 5.
2
triangle. The base of each triangle once measured
230 meters. The height of each triangle once mea- A. 6
sured 187 meters. The area of a triangle is one-half B. 28
the product of the base b and its height h.
C. 36
D. 10

Answer

A. Write an expression that represents the area of
one side of the Great Pyramid.
18