A chemist has one solution that has 50% acid. She has another solution that is 25% acid. How many liters of the 50% acid solution should she combine to get 10 liters of a 40% acid solution?

Step-by-step explanation:

Let's begin by assigning letters to represent our two unknowns:

   x (liters of 25% solution)

   y (liters of 50% solution)

Our system of equations will consist of two equations:

   Equation #1 (total volume of solution)

   Equation #2 (total concentration of acid)

Our total volume of solution is 10 liters, which can be expressed as the sum of our unknowns:

   Equation #1:  x + y = 10

Our total concentration of acid can be expressed as the sum of the individual acid concentrations to make up the concentration of the final solution:

   Equation #2:  (0.25)(x) + (0.50)(y) =

                            (0.40)(10)

We can use Equation #1 to express one unknown in terms of the other and then plug that expression into Equation #2 to solve for one of the unknowns:

   x + y = 10

         y = 10 - x

Now we'll plug our expression for y in terms of x into Equation #2 and solve for x:

   0.25(x) + 0.50(10 - x) = 0.40(10)

   0.25x + 5 - 0.50x = 4

   -0.25x = 4 - 5

   -0.25x = -1

          x = (-1)/(-0.25)

          x = 4 (liters of 25% solution)

Now we'll plug our value for x into Equation #1 and solve for y:

   4 + y = 10

         y  = 10 - 4

         y = 6 (liters of 50% solution)

Finally, we will verify the correctness of our answers by plugging these values into Equation #2 to see if the sum of the component acid concentrations equals the final solution concentration:

   0.25(4) + (0.50)(6) = 0.40(10)

   1 + 3 = 4

         4 = 4 (our answers are correct)

(1, –1), (16, –4), (36, –6)

step-by-step explanation:

given that the function is

this can also be written as

we have to graph this function and check which list of points lie on the graph

see attachment for graph:

we find that the points lying are (1,-1) (16,-4) and (36,-6)

since square root is there we find that x can only be posiitve but y can be since square root both positive and negative.

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