In the Figure below is shown the graph of this function. We have the following function:

The
occurs when
, so:

Therefore, the
is the given by the point:

From the figure we have three
:

So, the
occur when
. Thus, proving this:

"Bucket method"
.. (4)*(14%) + (x)*(8%) = (4 +x)*(10%) . . . . . liters and % are in each "bucket"
.. 56 +8x = 40 +10x . . . . . multiply by 100, eliminate parentheses
.. 16 = 2x . . . . . . . . . . . . . . add -40-8x, then divide by 2
.. 8 = x
8 liters of 8% lemonade should be added to make the mixture 10% lemon juice.
We need a picture of the shape.
The x-intercepts are (-1/2, 0) and (-1,0).
The y-intercept is (0,1).