Answer:
16 problems.
Step-by-step explanation:
100% divided by 20 questions.
100/20 is equal to 5, therefore each question is worth 5 points.
Grade of 80% divided by points per question.
80/5 is 16 so the student answered 16 questions correctly.
Answer:

Solving Steps
Use the quadratic formula

Multiply / Remove the parentheses / Evaluate

Calculate

Separate the solutions

Simplify

Answer:
good question
Step-by-step explanation:
(5,7) (5,4) (7,4) hope that helps