Answer:
What? I don't see anything.
Step-by-step explanation:
Solution: (-Infinite, -8/3] U (4, Infinite)
Using that a fraction is greater than or equal to zero when the numerator and denominator have the same sign:
a/b>=0. Then we have two cases:
Case 1) If the numerator is positive, the denominator must be positive too (at the same time):
if a>=0 ∩ b>0
Or (U)
Case 2) If the numerator is negative, the denominator must be negative too (at the same time):
if a<=0 ∩ b<0
In this case a=3x+8 and b=x-4, then:
Case 1):
if 3x+8>=0 ∩ x-4>0
Solving for x:
3x+8-8>=0-8 ∩ x-4+4>0+4
3x>=-8 ∩ x>4
3x/3>=-8/3 ∩ x>4
x>=-8/3 ∩ x>4
Solution Case 1: x>4 = (4, Infinite)
Case 2):
if 3x+8<=0 ∩ x-4<0
Solving for x:
3x+8-8<=0-8 ∩ x-4+4<0+4
3x<=-8 ∩ x<4
3x/3<=-8/3 ∩ x<4
x<=-8/3 ∩ x<4
Solution Case 2: x<=-8/3 = (-Infinite, -8/3]
Solution= Solution Case 1 U Solution Case 2
Solution = (4, Infinite) U (-Infinite, -8/3]
Solution: (-Infinite, -8/3] U (4, Infinite)
$2.99 for 450 gallons, 2.99(450), is $1345.50.
$3.49 for 450 gallons, 3.40(450), is $1570.50.
The profit difference, 1570.50-1345.50, is $225.
