Chapter 2 - Section 2.6 - Absolute Value Equations - Exercise Set - Page 100: 68

Solution set is $\{ \}$ or $ф$.

$|\frac{5d+1}{6}| = - |-9|$ Since $|-9| $ is $9,$ $-|-9| = -9.$ Given expression becomes, $|\frac{5d+1}{6}| = -9$ The result of the absolute value is always positive or zero. So this expression has no solution. Solution set is $\{ \}$ or $ф$.