When you're evaluating P(n, k), you are essentially saying there are n objects and you will need to arrange them in k spaces.
This is essentially the same as:

, which follows the formula:

If you're dividing by 4!, you are evaluating P(6, 2)
(10x+5) + (6x-1)=180
10x+5+6x-1=180
16x+4=180
16x+4=180
16x=180-4
16x=178
x=11
2+x = 2x -15
2+15=2x - x
17 = x
Answer:
6x-3
Step-by-step explanation:
remove breceket
3×2 =6
3×-1= -3
answer is 6x-3