Please answer the question down below also show the problem solving

Look at arnold's attempt to solve the equation for b: 3b = 12 b = 3 · 12 b = 36 describe the mistake that arnold made.

Let f(x) = 3 − x . find the average rate of change of f(x) from x = a to x = a + h and simplify your answer so that no single factor of h is left in the denominator.

1. evaluate 8x(2)y9(-2) for x=-1 and y=2 2. simplify the equation. -() 3. simplify the expression. [tex]\frac{5}{x(-2) y9(5)}[/tex]