Step 5 Therefore, T - 1 +81) dx = 16+1+*- 11 dx x2 + 81 -16-1 dx. 81 81 x2 + 81 Step 6 Using the substitution u = x - 1, we get the following. (Remember to use absolute values where appropriate.) dx = In(|x - 11) + C X-1 In - 11 Tx Step 7 Using the substitution u = x2 + 81, we get the following. (Remember to use absolute values where appropriate.) Sa+s1 Ox = { n( x2 +81) ln(x² +81) + c Step 8 Recalling that Tutus 1 1+ 4² du = tan-1 u, we get dx = x2 + 81 2. 1n (122+ +811) + C. X