Question

How do you do problems like x^2+x-20 less then or equal to 0 

I am clueless on how to do this. 
Please help me. >_<

Answer 1

`x^2+x-20\leq0\\ x^2+5x-4x-20\leq0\\ x(x+5)-4(x+5)\leq0\\ (x-4)(x+5)\leq0\\ x\in[-5,4]`