Algebraic Expressions 71
If an opposite (−) symbol immediately precedes parentheses that enclose an
algebraic expression, remove the parentheses and the opposite symbol and
rewrite the algebraic expression, but with all the signs changed.
Problem Simplify −−⎛ +−
⎝
⎛⎛⎛⎛
⎝⎝
⎛⎛⎛⎛ ⎞
⎠
⎞⎞⎞⎞
⎠⎠
8 5 ⎞⎞⎞⎞
2
xy^3227
x
.
Solution
Step 1. Remove the parentheses and the oppo-
site symbol and rewrite the expression,
but change all the signs.
−−⎛ +−
⎝
⎛⎛⎛⎛
⎝⎝
⎛⎛⎛⎛ ⎞
⎠
⎞⎞⎞⎞
⎠⎠
8 5 ⎞⎞⎞⎞=−+
2
27 8
5
2
xy^323227
x
xy
x
If a minus (−) symbol immediately precedes parentheses that enclose an
algebraic expression, mentally think of the minus symbol as “+−,” meaning
“add the opposite.” Then remove the parentheses and rewrite the algebraic
expression, but change all the signs.
Problem Simplify 10 −() 373 3277 ++ 22.
Solution
Step 1. Mentally think of the minus symbol as “+−.”
10 +−() 3 3277777 2 ++ 22
Do this mentally.
Step 2. Remove the parentheses and rewrite the algebraic expression, but
with all the signs changed.
10 −() 3373277 ++ 22 = 10 − 373 xx^3277 − 2 x
If a number immediately precedes parentheses that enclose an algebraic
expression, apply the distributive property to remove the parentheses.
P
P
P
−−⎛ +−
⎝⎜
⎛⎛
⎝⎝
⎞
⎠⎟
⎞⎞
⎠⎠
8 5 ≠+−
2
27 8 5
2
xy^323227
x
y
x
.
Change all the signs, not just the fi rst
one. This mistake is very common.