Deandre = x
Kala = x + 6
Eric = 3(x+6)
x + x + 6 + 3(x+6) = 119
2x + 6 + 3x + 18 = 119
5x + 24 = 119
5x = 95, x = 19
Deandre has $19
Kala has 19 + 6 = $25
Eric has 3(25) = $75
The plus-minus sign represents that there are two possible outcomes.
In this case, we have

. When we branch out the possibilities we got 2 values:

and

Those are the roots of this equation. When they ask their product, they want you to multiply both numbers.
When we multiply them:

When we FOIL the we get:

Simplify:


So the product of the two roots of this equation is 6.
There are certain rules to follow when rotating a point 90 deg clockwise. Since it is given that ABCD is a parallelogram and the coordinates of point C are given, we just have to follow this simple relation:
R(90 deg) : (X,Y) ---> (-Y,X)
Using the given coordinates:
R(90 deg<span>) : (-4,1) ---> (-1,-4)
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Therefore, Point C' will be located at (-1,-4)
15% of 40 is 6
Hope this helps :D