Answer
$(a)$ Algebraically we simply place the unknown variable on the one side of inequality and simplify, so we will get a set of solution.
$(b)$ Using graphical method, we have to move all the terms to one side of the inequality, then set the set of terms equal to $y$. Simply solve the equation and find the graph of it. And at last determine where the graph is above or below $x$-axis (based on the sign of inequality).
Work Step by Step
$(a)$ Algebraically we simply place the unknown variable on the one side of inequality and simplify, so we will get a set of solution.
$(b)$ Using graphical method, we have to move all the terms to one side of the inequality, then set the set of terms equal to $y$. Simply solve the equation and find the graph of it and at last determine where the graph is above or below $x$-axis (based on the sign of inequality).
(Also explained in chapter $1.11$ of textbook.)
