Carcass wrote:
Which of the following numbers satisfies the absolute value inequality shown?
\(|2x-1|>5\)
Indicate all such numbers
A. \(- \pi\)
B. \(- \frac{3}{2}
\)
C. \(- \sqrt{10}
\)
D. \(\frac{\sqrt{2}}{2}\)
E. \(2 \pi\)
When solving inequalities involving ABSOLUTE VALUE, there are 2 things you need to know:
Rule #1: If |something| < k, then –k < something < k
Rule #2: If |something| > k, then EITHER something > k OR something < -kNote: these rules assume that k is positiveSo, if \(|2x-1|>5\), we can conclude that EITHER \(2x-1>5\) OR \(2x-1< -5\)
Now let's solve each of the resulting inequalities:
Take: \(2x-1>5\)
Add 1 to both sides: \(2x>6\)
Divide both sides by 2 to get:
\(x>3\)Take: \(2x-1<-5\)
Add 1 to both sides: \(2x<-4\)
Divide both sides by 2 to get:
\(x<-2\)So, we're looking for any answer choice that satisfies either inequality (
\(x>3\) or
\(x<-2\))
A. \(- \pi ≈ -3.14\). This
satisfies the inequality
\(x<-2\)B. \(- \frac{3}{2} = -1.5\). This satisfies neither inequality.
C. \(- \sqrt{10}≈ -3.something\). This
satisfies the inequality
\(x<-2\)D. \(\frac{\sqrt{2}}{2}≈\frac{1.4}{2}≈0.7\). This satisfies neither inequality.
E. \(2 \pi\)≈(2)(3.14) ≈ 6.28[/quote]. This
satisfies the inequality
\(x>3\)Answer: A, C and E