Mariana and bethany disagree about whether the set of polynomials is closed under addition, subtraction, and multiplication, as the set of integers is. to examine their two positions, they consider the polynomials a = 5x − 1 and b = 2x. mariana thinks these polynomials are closed under all three operations. bethany argues that these polynomials are closed under only two operations. complete the following statements, and then determine who is correct.
a + b = a − b = a • b = 10x2 + correct.

Students at a high school were asked about their favorite outdoor activity. the results are shown in the two-way frequency table below. fishing camping canoeing skiing total boys 36 44 13 25 118 girls 34 37 22 20 113 total 70 81 35 45 231 select all the statements that are true based on the given table. more girls chose camping as their favorite outdoor activity than boys. more girls chose canoeing as their favorite outdoor activity than those who chose skiing. more boys chose skiing as their favorite outdoor activity than girls. there were more boys surveyed than girls. twice as many students chose canoeing as their favorite outdoor activity than those who chose fishing. more students chose camping as their favorite outdoor activity than the combined number of students who chose canoeing or skiing.