how do you find the missing number/what is the missing number?

Solving a Single Variable Equation :

Solve  :    3x+1 = 0

Subtract  1  from both sides of the equation :

                3x = -1

Divide both sides of the equation by 3:

         x = -1/3 = -0.333

One solution was found :

         x = -1/3 = -0.333

r(0,90)(x,y) . t(-5,0)

last option

step-by-step explanation:

∆def to ∆d"e"f"

- rotate 90 counterclockwise degrees

- then translated 5 to the left (x --> x - 5)

answer is the last option

i believe the answer is the polygon, heptagon.