The difference between a number and 12 is 20

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

Stu and ambrose are working together on a study of whether diet is related to students' mental health. first, they randomly select 10 students from the student center and 10 students from the office of counseling and psychological services. then, they ask students to rate their diet in terms of healthiness on a scale of 1-100 before completing a 20-item mental health survey. a) name one of the constructs being studied b) how was the construct you named above operationally defined in this experiment? e) was the variable you described above their independent variable, their dependent variable, or a controlled variable? d) what is a confounding variable? what is a potential confound in this study?

Aband wants to create a cd of their last concert. to creat the cds, the cost will be $350 advertisement fee plus $3 per cd.write an inequality that represents how many cds they can buy with a maximum of $1225.solve the inequality