let there are x number of trees
Justus samples 3 oranges from one tree
Number of oranges he samples from x trees =3x
Extra oranges =50
total number of oranges = 3x+50
as a function f(x) we can write it as
f(x) =3x+50
B. Fractions have to have the same denominator so

which =

then you simplfy it to

so it would be B
X^2 + 10x + 11 = 0
x^2 + 10x = -11
x^2 + 10x + 25 = -11 + 25
(x + 5)^2 = 14 <===
x + 5 = (+-) sqrt 14
x = -5 (+-) 3.74
x = -5 + 3.74 = -1.26 <== solution
x = -5 - 3.74 = - 8.74 <== solution
2×$15.99=31.98
+ 4×$11.99=47.96
---------------
$79.94
:. $79.94 is the cost.