Help me please and thank you :DD

Write a function for a rotation 90 degrees counter clockwise about the origin, point 0

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?

Rose and andrew are financing $128,000 to purchase a condominium. they obtained a 15-year, fixed-rate loan with a rate of 5.05%. they have been given the option of purchasing up to four points to lower their rate to 4.81%. how much will the four points cost them?