Pls asap for 20 points i will mark correct brainle est might be easy. how many 4-digit numbers can you write if you cannot use any other digits except 0 and 2?

You can write the combination formula which is in the picture. Now if you can't guess what the varibles mean I'll tell you. N is the amount of digits you're allowed to use, and k is the amount of spots allowed in a number. Plus if the factorial sign or ! isn't part of your common knowledge, it means to multiply all  below it stopping at 1. Finally if you comput your information into the formula you find out that there's 24 combinations. I hope this answers your question.

area of part 1:

a1=base*height/2=(8+2)*(8-2-2-1)/2=10*3/2=15 ft^2

area of part 2:

a2=length*width=(8+2)*1=10 ft2

area of part 3:

a3=length*width=8*2=16 ft2

total shaded area : a1+a2+a3=41 ft2

total area of the reactangle : a=16*8=128 ft2

total area of the nonshaded region : 128-41=87 ft2

i dont know

step-by-step explanation: