A food truck vendor averages $150$150​ tacos sold when the price per taco is $\$4$$4​ . A study shows that the average number of tacos sold will increase by $25$25​ tacos for every $\$1$$1​ that the price per taco is lowered. Which equation models the food truck's average sales in dollars, $s$s​ , in terms of the price per taco, $x$x​ ?

How can you tell when x and y are not directly proportional?

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

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