First, we simplify 6x+2y=36 into 3x+y=18 by dividing by 2. This means that y=-3x+18.
The sum

can be written as:

,
<span>
from the binomial expansion formula: </span>

.
<span>
Thus, substituting </span>y=-3x+18 and simplifying we have<span>
</span>



.
This is a parabola which opens upwards (the coefficient of x^2 is positive), so its minimum is at the vertex. To find x, we apply the formula -b/2a. Substituting b=-108, a=10, we find that x is 108/20=5.4.
At x=5.4, the expression

, which is equivalent to

, takes it smallest value.
Substituting, we would find

=32.4 This is the smallest value of the expression.
For x=5.4, y=-3x+18=-3(5.4)+18=1.8.
Answer: (5.4, 1.8)
<span>Orthocenter is at (-3,3)
The orthocenter of a triangle is the intersection of the three heights of the triangle (a line passing through a vertex of the triangle that's perpendicular to the opposite side from the vertex. Those 3 lines should intersect at the same point and that point may be either inside or outside of the triangle. So, let's calculate the 3 lines (we could get by with just 2 of them, but the 3rd line acts as a nice cross check to make certain we didn't do any mistakes.)
Slope XY = (3 - 3)/(-3 - 1) = 0/-4 = 0
Ick. XY is a completely horizontal line and it's perpendicular will be a complete vertical line with a slope of infinity. But that's enough to tell us that the orthocenter will have the same x-coordinate value as vertex Z which is -3.
Slope XZ = (3 - 0)/(-3 - (-3)) = 3/0
Another ick. This slope is completely vertical. So the perpendicular will be complete horizontal with a slope of 0 and will have the same y-coordinate value as vertex Y which is 3.
So the orthocenter is at (-3,3).</span>
Its A trapezium
For Calculations Refer to the attachment