1. For the function f(x)=ax^3 +bx^2-5x +9, determine the values of a and b so that f(-1)=12 and f'(-1)=3
2. Determine the equations of two lines that pass through the point (-4,-5) and are tangent to the graph of y=x^2 +1
3. Two particles have positions at time t given by s1=4t-t^2 and s2=5t^2-t^3. When the acceleration of the two particles are equal, find the positions and velocities of both particles.