Answer:
Step-by-step explanation:
n x 5
28 - 2.2x = 11.6x - 54.8
28 + 54.8 = 11.6x + 2.2x
82.8 = 13.8x
82.8 / 13.8 = x
6 = x
or x = 6
Answer:
B
Step-by-step explanation:
C and D aren't linear and A has a positive slope
Let x gallons be the amount of pure antifreeze that should be added to the 30% solution to produce a solution that is 65% antifreeze. Then the total amount of antifreeze solution will be x+3 gallons.
There are 30% of pure antifreeze in 3 gallons of solution, then
3 gallons - 100%,
a gallons - 30%,
where a gallons is the amount of pure antifreeze in given solution.
Mathematically,

Now in new solution there will be x+0.9 gallons of pure antefreeze.
x+3 gallons - 100%,
x+0.9 - 65%
or

Answer: he should add 3 gallons of pure antifreeze.