So, Rana is trying to <em>multiply her hours with her earnings to get the product</em>, that's where the variable<em> E</em> is. <em>H</em> stands for hours, and so you will <em>multiply it by 20 </em>because that's how much she gets per hour.
-Junkerss
edit: yes im the original person who wrote this answer if anyone is c & p it.
Hello : a reasonable domain for this function is : <span>]0
; + ∞[<span> because : x </span></span>> 0 and x+4 > 0 .... f(x) = x(x+4) ... length ×<span>width</span>