Tests for math equations

math elements with overlow-x: auto;

P ( x ) = x n + b 1 x n 1 + + b n 1 x + b n = ( x x 1 ) ( x x n ) . {\displaystyle P(x)=x^{n}+b_{1}x^{n-1}+\cdots +b_{n-1}x+b_{n}=(x-x_{1})\cdots (x-x_{n}).}