Answer:
Check below for step-by-step guide.
Explanation:
a) Recall the formula for area is length times width. You are given both of those values. Width= (5x+2) and length = (4x-1). All you have to do is multiply them. You will get a quadratic!
b) This is just basically a lot of plugging in to the equation: Volume= length x width x height. So let's look at what we have!
It says our volume is 20x^3 + 63x^2+ 7x-6
It says our width is : (5x+2)
It says out length is (4x-1).
So the volume = l x w x h , we just plug in those numbers I listed above :
20x^3 + 63x^2+ 7x-6= (4x-1) (5x+2) (height)
Now remember you already multiplied length times width in problem (a). You can use that expanded quadratic on the right side. Then subtract values and isolate height!
You asked for an explanation of what to do step by step, so if you actually need help solving it, comment please! :)