Answer:
C. a = 7
D. c = -3
Step-by-step explanation:
C. 7(2a + 3) + 21 = 100+ 40
14a + 21 + 21 = 140
14a = 140 - 21 - 21
14a = 98
a = 7
D. 6+ 14 - 12c = 56
20 - 12c = 56
-12c = 56 - 20
-12c = 36
c = - 3
A plastic skeleton is
Answer: B. a physical model.
The world has lots of different kinds of models. A mathematical model might be a ball travels according to the equation 
. This isn't that. A computer model would be a program that somehow simulates a skeleton in the computer, this isn't that either. Our skeleton is an actual physical model just like a model airplane.
Stack them on top of each other and find the common denominator then multiply to total the denominator. Ex. 1/4 denominator is 8. 4x2 is 8. So 1 times what equals 8. 1! Then you should a new fraction 8/8 which is equivalent to 1.
Circumference = π * d
π=3.14
diameter = 6
3.14 * 6 = 18.84.
The answer is A.
Hope this helped☺☺
