The sum of a number and 5 is tripled then lessened by 15 to get 9

What is the result of adding the system of equations? 2x+y=4 3x-y=6

Can someone answer this question for me

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