Answer:
6,840 casts
Step-by-step explanation:
Assuming that every actor can play each of the 4 roles and that each role is different, the number of possible casts including at least one of sir Ian and Patrick is given by the total number of possible casts (permutation of 4 out of 12 actors), minus the number of casts without sir Ian and Patrick (permutation of 4 out of 10 actors):

There are 6,840 possible casts.
Under a counterclockwise rotation about the origin of 90°
a point (x , y ) → (- y, x ), hence
A(2, 1 ) → A'(- 1, 2 )
Solve algebrically 3x - 4y = -24 and x + 4y = 8 is x = -4 and y = 3
<u>Solution:</u>
We have been given two equations which are as follows:
3x - 4y = -24 ----- eqn 1
x + 4y = 8 -------- eqn 2
We have been asked to solve the equations which means we have to find the value of ‘x’ and ‘y’.
We rearrange eqn 2 as follows:
x + 4y = 8
x = 8 - 4y ------eqn 3
Now we substitute eqn 3 in eqn 1 as follows:
3(8 - 4y) -4y = -24
24 - 12y - 4y = -24
-16y = -48
y = 3
Substitute "y" value in eqn 3. Therefore the value of ‘x’ becomes:
x = 8 - 4(3)
x = 8 - 12 = -4
Hence on solving both the given equations we get the value of x and y as -4 and 3 respectively.
Rule of trigonometric functions:-
sin a = cos(90 - a)
Here a = 90°.
sin 90 = cos (90 - 90)
1 = cos 0.
cos 0 = 1.
So the cos 0 = 1.