Profit = Revenue - Cost = R(x) - C(x) = (x^2 + 20x + 50) - (50x + 30) = x^2 - 30x + 20
D.
Explanation
I saw this answer in a different question today.
Moreover, 1n + 0.25n = 1.25n
Answer: 
Explanation:
Follow PEMDAS in reverse to undo what's happening to x.
We first add 1 to both sides, then divide both sides by 5 to fully isolate x.
Refer to the steps below to see what I mean.

The inequality sign stays the same the entire time. The only time it flips is when you divide both sides by a negative number.
The solution set for x is anything -3 or larger.
If x was an integer, then we could say the solution set is {-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, ...}
(f+g)(x) just means f(x) + g(x)

Choice B
Answer:
BC=10
Step-by-step explanation:
BD-BC=14-4=10