Let x=amount of 50% solution and y=amount of 80% solution.
x+y=600 gallons; amount of pure acid in the mixture has to be 72% of 600=432 gallons.
So 0.5x+0.8y=432; but y=600-x so 0.5x+0.8(600-x)=432, 0.5x+480-0.8x=432.
480-432=0.3x, 48=0.3x so x=160 so y=600-160=440 gallons.
160 gallons of 50% and 440 gallons of 80%.
√x+5 -1 = 0
Solve for X:
Add 1 to each side:
√x+5 = 1
Remove the radical by squaring both sides:
(√x+5)^2 = 1^2
Simplify:
x+5 = 1
Subtract 4 from each side:
x = -4
The answer is C.
Step-by-step explanation:

× All by x(x-2) both sides of equation
(x-2)-x = 3x(x-2)
x-2-x = 3x² - 6x
-2 = 3x² - 6x
0 = 3x² - 6x +2
3x² - 6x + 2 = 0
and use the formula

Answer:
3.8
Step-by-step explanation: