Who can help me on my math I’m failing can y’all please help me on some questions.
It’s solving systems of equations

Answer:
Lowest: 78
Highest: 99
Step-by-step explanation:
Quiz 1 =A
Quiz 2 = B
B = 21 + A
2A = 57 + B
2A = 57 + (21 + A)
2A = 78 + A
A = 78
B = 21 + A
B = 21 + 78
B = 99