Answer:
7
Step-by-step explanation:
mean means average
there are 8 numbers
add them all up
7+8+9+2+4+5+12+9=56
divide 56 by 8 = 7
-2 1/2 - (-1 3/4)
When subtracting a negative vile the equation becomes addition:
-2 1/2 + 1 3/4 = -3/4
Answer: -3/4
1.BE = 2x + 6
ED = 5x - 12
2. To get the entire side of BD, we must add both half's which equals to the entire length.
3. 2x + 6 + 5x - 12
4.Add like terms.
2x + 5x = 7x
-12 + 6 = -6
5. So, we have 7x - 6
=7x - 6
2(5*10)+2(10*4)+2(5*4)=
2(50)+2(40)+2(20)=100+80+40=
220 cm^2
I found the answer by finding the areas of the 3 different sides, multiplying each area by 2 since each side has another side that is equal on a rectangular prism, then adding all of them together.
I believe the answer is D but i could be wrong. sry for not being absolutely sure.
lol