Make sure that you have actually entered an equation or inequality (it needs to contain =, <, >, >= or <= symbol).

For example, -5x^2+30x+1 is not an equation – it is an expression.

On the other hand, -5x^2+30x+1 = 0 is an equation which can be solved (for either one of the variables).

click here to see the solution for -5x^2+30x+1 = 0

 

On the other hand, if you have the solutions for -5x^2+30x+1 = 0 you can write:

Using the fact that you can factorize quadratic equation ax^2 + bx + c = 0 with roots x1 and x2:

ax^2 + bx + c = a(x - x1)(x - x2)