i need help i dont understand this

Answer:
D
Step-by-step explanation:
Given the 2 equations
4x + 8y = 21 → (1)
y = - [tex]\frac{1}{2}[/tex] x + 3 → (2)
Substitute y = - [tex]\frac{1}{2}[/tex] x + 3 into (1)
4x + 8(- [tex]\frac{1}{2}[/tex] x + 3 ) = 21 ← distribute parenthesis on left side
4x - 4x + 24 = 21 ( subtract 24 from both sides )
0 = - 3 ← not possible
This indicates the system has no solutions