Answer:
A=z
B=-2
C=0
D=30
Step-by-step explanation:
First lets simply the equation
21 - (2x +3)2 + 4(1-1) + z^3
21 - (2x^2 + 9) + 4(0) + z ^3
21 - 2x^2 + 9 + z^3
- 2x^2 + z ^3 + 30
This means that:
A=z
B=-2
C=0
D=30
The answer is B. The values of y must only be positive because it is equal to

The other options states that the values of y could be negative which is why it is wrong.
Equation: bh
Equation: 6.2x2.4=14.88 inches^2