Khan Academy Question pls answers only

Suppose the radius of a circle is 16. what issuppose the radius of a circle is 16. what is its circumference its circumference

Given: f(x) = 2x + 5 and g(x) = x2 and h(x) = -2x h(g(f( = x2+ vx+ x + y

Consider the reaction 2x2y2+z2⇌2x2y2z which has a rate law of rate= k[x2y2][z2] select a possible mechanism for the reaction.