11.9 gallons. Hope I helped!
We know that : Sum of Angles in a Triangle is equal to : 180°
⇒ In ΔRST, The Sum of Angles ∠R , ∠S , ∠T should be equal to 180°
⇒ m∠R + m∠S + m∠T = 180°
⇒ (2x + 10)° + (2x + 25)° + (x - 5)° = 180°
⇒ (2x + 2x + x) + (10° + 25° - 5°) = 180°
⇒ 5x + 30° = 180°
⇒ 5x = 180° - 30°
⇒ 5x = 150°
⇒ x = 30°
Apply the "FOIL" method here. (m+1)(m+1) = m^2 + 1m + 1m + 1, or m^2 + 2m + 1.
Your answer would be A)
Hope this helps (:
To solve the inequality 

The numerator
is not factorizable.
so factor the denominator
:

Now take 
Then we get factor of the denominator as 
Thus 
Now 
Signs of 

is the required solution of the given inequality.