50

i really need the work though, not just the

!

f(x) = 9x^3 + 2x^2 - 5x + 4 > 9x^3 + 2x^2 - 5x + 4
g(x) = - (5x^3 - 7x + 4) > - 5x^3 + 7x - 4
4x^3 + 2x^2 + 2x > 0

I hope this helps you out because I just spent a lot of time figuring it out myself ad typing it out.

I hope it doesn't look too messy:

(x)=9x^3+2x^2-5x+4 and g(x)=5x^3-7x+4 
so, by DEFINITION : 
(f-g)(x) = f(x) - g(x) 
= (9x^3 + 2x^2 - 5x + 4) - (5x^3 -7x + 4) 
= 9x^3 + 2x^2 - 5x + 4 - 5x^3 + 7x - 4 <--- sign rule 
= 4x^3 + 2x^2 + 2x 

(0, 0), (0, 15), (20, 25), (40, 0)

Step-by-step explanation:

The diagram shows shaded region in the form of quadrilateral bounded with two given lines and x- axis and y-axis. Four vertices of this quadrilateral are point of intersection of those lines or lines with coordinate axes.

The first vertex of this quadrilateral lies at the origin (point of intersection of two axes), then its coordinates are (0,0).

The second vertex lies on the x-axis and its coordinates are (40,0) (placed at 40 on the x-axis)

The third vertex lies on the y-axis and its coordinates are (0,15) (placed half way between 10 and 20 on the y-axis).

The fourth vertex is the intersection of two lines. Its coordinates are (20,25) (draw vwrtical line from this vertex t x-axis, it will intersect x-axis at 20, draw horizontal line to y-axis, it will intersect the y-axis at 25).

So, correct option is A: (0, 0), (0, 15), (20, 25), (40, 0)