In a parallelogram, the opposite angles will be congruent to each other.
In this parallelogram, angles B and C are congruent, and angles A and D are congruent.
We will work on angles B and C first. Set the two angles to equal each other:

Subtract 6 from both sides:

Subtract 6x from both sides:

Divide both sides by 6 to get x by itself:

x will equal 10.
Set angles A and D to equal each other:

Divide both sides by 3 to get y by itself:

y will equal 18.
The x and y values that make this quadrilateral a parallelogram will be x = 10, and y = 18.
Answer:
x - 8y - z = 1
Step-by-step explanation:
Data provided according to the question is as follows
f(x,y) = z = ln(x - 8y)
Now the equation for the tangent plane to the surface
For z = f (x,y) at the point P
is

Now the partial derivatives of f are


= 1
Now

= -8
So, the tangent equation is

Now after solving this, the following equation arise
z = x - 9 - 8y + 8
z = x - 8y - 1
Therefore
x - 8y - z = 1