Which of the quadratic functions has a graph that opens downward?
check all that apply

a. y=5/2x-3x^2
b. y=-(2x^2-1)
c. y=3/2x^2-3x+15
d. y=3x^2-x-1

Question 1 of 10 2 points different groups of 50 graduates of an engineering school were asked the starting annual salary for their first engineering job after graduation, and the sampling variability was low. if the average salary of one of the groups was $65,000, which of these is least likely to be the average salary of another of the groups? o a. $64,000 o b. $65,000 o c. $67,000 o d. $54,000

Solve this 364x-64x=300x and 12(x2–x–1)+13(x2–x–1)=25(x2–x–1)

Acontainer holds 0.7 liters of oil and vinegar. 3/4 of the mixture is vinegar. how many liters of oil are in the container? express your answer as both a fraction and a decimal.