Please help, tysm for your assistance if you do :)

Which of these is and example of a literal equation? a) 6+30=6^2 b)3x-4y c)12=9+3x d)ax-by=k

Aboat costs 19200 and decreases in value by 12% per year. how much will it cost in 5 years

If (x + 8) is a factor of f(x), which of the following must be true? both x = –8 and x = 8 are roots of f(x). neither x = –8 nor x = 8 is a root of f(x). f(–8) = 0 f(8) = 0