I'm having the same troubles with this type of geometry sort of.
x
(15) sin 30.5 = ------ (15)
15
(15) sin 30.5 = x
Plug this part into a calculator.
7.61 = x
Area of a triangle: 1/2bh
1/2 (7.61)(13)
3.805(13)
49.469
49.47 un² is your final answer since you are supposed to round to the tenths place. I hope this helps.
B+1 is not possible to be 0
for this b+1≠0, b ≠ -1
-1 is the value