This is not a polynomial equation unless one of those is squared. As it stands x=-.833. If you can tell me which is squared I can help solve the polynomial. Ok, that is usually notated as x^3 to be clear. I'll solve it now. x^3-13x-12=0 Then use factor theorum to solve x^3-13x-12/x+1 =0 So you get one solution of x+1=0 x=-1 Then you have x^2-x-12 now you complete the square. Take half of the x-term coefficient and square it. Add this value to both sides. In this example we have:The x-term coefficient = −1The half of the x-term coefficient = −1/2After squaring we have (−1/2)2=1/4When we add 1/4 to both sides we have:x2−x+1/4=12+1/4STEP 3: Simplify right sidex2−x+1/4=49/4STEP 4: Write the perfect square on the left.(x−1/2)2=49/4 STEP 5: Take the square root of both sides.x−1/2=±√49/4 STEP 6: Solve for x.x=1/2±√49/4that is,x1=−3x2=4and the one from before x=-1

This is not a polynomial equation unless one of those is squared.