Square Roots of a Quantity Squared An important form of a square root is: It would seem that we should write … … but as we shall see, this is not always the case.
Example 1Note the patterns here. Same Opposite in sign
Recall that the absolute value of a negative number is the opposite of that number. We now define …
Example 2 Simplify
Example 3 Simplify Since x + 2 could be negative for certain values of x, we must keep the absolute value sign.
Example 4 Simplify First write the radicand as a quantity squared. Sinceis always nonnegative, the absolute value sign is not necessary.
Example 5 Simplify First write the radicand as a quantity squared. Sincewould be negative if a were negative, the absolute value sign is necessary.
Example 6 Simplify Try to create the pattern of To do this, factor the radicand.
Since 4x - 5 could be negative for certain values of x, we must keep the absolute value sign.
Sometimes the directions will include a statement that the values of the variables will be such that the radicand will be nonnegative. In this case, the absolute value sign is not necessary.
Example 7 Simplify the expression, assuming that the variable represents a nonnegative value. Since the variable can’t be negative, the absolute value sign is not necessary.