Help me please I beg of you

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)

20 points plus brainliest andwer plus my hover hoard im v desperate ! evaluate the polynomial for x=-2 in the equation -3x^3+7x^2-7x-1 (simplify your answer)

Acube has a volume of 800 cubic inches. whatis the length of an edge of the cube, in inches? a. 23/100b. 43/50c. 83/100d. 1003/2e. 1003/8