Answer:
576 students choose cheeseburgers
Step-by-step explanation:
Given: In a survey, it was determined that 40% of students preferred pizza, 32% of students preferred cheeseburgers, and 28% of students preferred tacos.
To find: Number of students out of 1800 who choose cheeseburgers
Solution:
Percentage of students who preferred cheeseburgers = 32%
Total number of students = 1800
Number of students out of 1800 who choose cheeseburgers = 
Solve for r using factoring:
Solve for r:
r^2 - 8 r - 33 = 0
The left hand side factors into a product with two terms:
(r - 11) (r + 3) = 0
Split into two equations:
r - 11 = 0 or r + 3 = 0
Add 11 to both sides:
r = 11 or r + 3 = 0
Subtract 3 from both sides:
Answer: r = 11 or r = -3
If I’m right I think the answer is 1,759.32