If x + y = 9, z + y = 12, and z + x = 11, what is the average (arithmetic mean) of x, y and z?

graph #4 (last graph) depict the function   f(x)= -m(x-d)^1/5 i

step-by-step explanation:

we know that

m=slope

but in this function slope is -m that means slope is decreasing and it is decreasing by 1/5 points down the x-axis.

which is shown in graph four

a decreasing slope down x-axis by 1/5 points.

hence 4th graph is the right option for this.

the answer is a, biohazard symbol