Modulo one of the primes 151 and 157 the polynomial $x^2+$ $2 x-1$ has two roots, and modulo the other it has none. Use Jacobi's tables to determine which is which, and find the roots in the case in which there are roots. Verify that $x^2+2 x-1 \equiv\left(x-r_1\right)\left(x-r_2\right) \bmod p$, where $p$ is the prime for which there are two roots and $r_1$ and $r_2$ are the roots.