Which of the following are polynomials?
i. f(x)=3√x4−23x6+8.7
ii. g(x)=ln(7x3+5)
iii. h(x)=6ex5−3x4
iv. j(x)=7x3+5x49x6
v. k(x)=3x8.7+6x23−8
vi. f(x)=10
vii. g(x)=−6x−7+6x−4−27
viii. h(x)=4xπ+18x4+35

Tommy buys a sweater that is on sale for 40% off the original price. the expression p -0.4p can be used to find the sale price of the sweater, where p is the original price of the sweater. if the original price of the sweater is 50, what is the sale price?