Guys, my teachers keeps giving me C's for assignments im doing right! Can I switch teachers its only the 3rd week of school..?

Nine more than four times a number is the same as one less than twice the number. find the number?

Me. i can't figure out this question. give an explanation too. .

Atype of plant is introduced into an ecosystem and quickly begins to take over. a scientist counts the number of plants after mmonths and develops the equation p(m)= 19.3(1.089)^m to model the situation. most recently, the scientist counted 138 plants.assuming there are no limiting factors to the growth of the plants, about how many months have passed since the plants werefirst introduced? a)o 6.1b)0.6.6c)10 72d)o 23.1