Christine buys 7 hamburgers and 3 sodas for $27.95. laura buys 5 hamburgers and 4 sodas for $23.40. how much does a hamburger cost?
a. 1 .85
b. $3.20
c. $6.80
d. $6.55
e. $3.50

How do i do this activity, is appreciated

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)

Use sigma notation to represent the following series for 9 terms.