2.21 x 10^17 and the answer is 2.21e+17
W = 7/15 L
w = 56
56 = 7/15 L
56 x 15/7 = 7/15 x7 L
L = 120
Complentary angles add to 90 degrees
a and b are complentary
a+b=90
a=7x+4
b=4x+9
so
7x+4+4x+9=90
combine like terms
11x+13=90
minus 13 both sides
11x=77
divide both sides by 11
x=7
m a =7x+4=7(7)+4=49+4=53
m b=4x+9=4(7)+9=28+9=37
angle a measures 53 degrees
angle b measures 37 degrees
For this case we must find the slope of the following equation:

By definition, the point-slope equation of a line is given by:

Where:
: It is a point through which the line passes
m: It's the slope
So, the slope of the given equation is:

Answer:
Option D