easy math graphing problem, not sure how to do?

Question

its here but i dont know how to graph it.. http://public.fotki.com/wazzzzaaaas/mark/mathxl.html

Answer 1

4
∫(2x + 5)dx
0
Graph the function (2x+5) from x = 0 to x = 4 and find the area under the curve (line). Since you have a linear function, you will have a trapezoid with b1 = 5, b2 = 13, and h = 4, and the area is 2(5 + 13) = 36, which is the solution of the definite integral.

Evaluating the integral, you get 4^2 + 5*4 - 0 - 0 = 36

Answer 2

The integration of the equation from 0 to 4
You can break down the 2x+5 into two integrals
1. I do not have an integral sign on the keyboard so this may be sort of hard to do. But here goes
integrate the 2xdx from 0 to 4
integrate the 5dx from 0 to 4
the 2 is a constant so it goes outside (to the left) of the integral
sign and you integrate from0 to 4 the xdx and that is (x^2)/2 and then you multiply this by the 2 that you put to the left of the integral and that leaves you with 2x^2/2. You then substitute the 4for the x and you get 2(4^2)/2=16
The other part of the equation was integrating from0 to 4 the constant 5dx and this simply is 5.
So, you get 16+5=21
y=21 and is therefore a straight line parallel with the x axis and is 21 units up on the xy axis. Note, y is +and therefore is on the + side of the 0.