True or explain why if false let the function f be differentiable on an interval i containing c. if f has a maximum value at x = c, then f has a minimum value at x = c. a cubic function defined by f(x)= ax^3+bx^2+cx+d where a does not equal 0 will always have exactly three critical numbers

As this is a trinomial function I believe the answer is true due to the fact that a trinomial curve consists of three parabolic curves in which each has its own respective minimum or maximum value i.e. critical number.

solve systems of equations by graphing. a system of linear equations contains two or more equations e.g. y=0.5x+2 and y=x-2. the solution of such a system is the ordered pair that is a solution to both equations. to solve a system of linear equations graphically we graph both equations in the same coordinate system