Find Zeros: Find the zeros of the quadratic expression by setting (x−1)(x+1)=0.x−1=0 gives x=1.x+1=0 gives x=−1.Critical points are x=1 and x=−1.
Determine Sign: Determine the sign of (x−1)(x+1) in each interval created by the critical points: (−∞,−1), (−1,1), and (1,∞).
Test Intervals: Test a point in the interval (−∞,−1), say x=−2.(x−1)(x+1) at x=−2 is (−2−1)(−2+1)=(−3)(−1)=3, which is positive.
Combine Intervals: Test a point in the interval (−1,1), say x=0. (x−1)(x+1)atx=0is(0−1)(0+1)=(−1)(1)=−1, which is negative.
Combine Intervals: Test a point in the interval (−1,1), say x=0. (x−1)(x+1) at x=0 is (0−1)(0+1)=(−1)(1)=−1, which is negative.Test a point in the interval (1,∞), say x=2. (x−1)(x+1) at x=2 is (2−1)(2+1)=(1)(3)=3, which is positive.
Combine Intervals: Test a point in the interval (−1,1), say x=0. (x−1)(x+1) at x=0 is (0−1)(0+1)=(−1)(1)=−1, which is negative.Test a point in the interval (1,∞), say x=2. (x−1)(x+1) at x=2 is (2−1)(2+1)=(1)(3)=3, which is positive.Combine the intervals where (x−1)(x+1) is positive. The solution is x=01 or x=02.