McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
5. Radical Equations
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Exercise 35 Page 262

When finding the principal square root of an expression including a variable, we have to be sure that the result is non-negative.

Sometimes

Practice makes perfect
We will explain if the given radical equation is always, sometimes, or never true. sqrt((x-2)^2)=x-2 Recall that when finding the principal square root of an expression including a variable, we have to be sure that the result is non-negative. Note that the given equation is not true for x<2 because if x is less than 2, then the result will be negative. As an example, let's substitute x= 1 in the equation and check if it produces a true statement.
sqrt((x-2)^2)=x-2
sqrt(( 1-2)^2)? = 1-2
sqrt((- 1)^2)? =- 1
sqrt(1)? =- 1
1≠ - 1 *
As we can see, the equation is not true for 1. On the other side, it is true for x≥ 2 because if x is greater than or equal to 2, then the result will not be negative. To illustrate, let's substitute x= 3 into the equation and check if it makes the equation true.
sqrt((x-2)^2)=x-2
sqrt(( 3-2)^2)? = 3-2
sqrt((1)^2)? =1
sqrt(1)? = 1
1=1 âś“
Therefore, the given equation is sometimes true.