Answer: x=25
solution:
we know that
The triangle external angle theorem states that: An exterior angle of a triangle is equal to the sum of the opposite interior angles
In this problem:
m∠9=m∠7+m∠8
substitute the given values:
(6x-20)°=30°+4x°
now solve for x:
6x-4x=30+20
2x=50
x=25 which is the final answer:)
For this case we have by definition, that the equation of a line in the slope-intersection form is given by:

Where:
m: It's the slope
b: It is the cutoff point with the y axis
We need two points through which the line passes to find the slope:

We found the slope:

So, the equation is of the form:

We substitute a point to find "b":

Finally, the equation is:

Answer:
Option C
You can line up 8 cards 64 different ways.
8 * 8 = 64