题目解方程:(1)x2−1=3(x+1)(1)x^{2}-1=3\left(x+1\right)(1)x2−1=3(x+1)；(2)x2+2x−1=0(2)x^{2}+2x-1=0(2)x2+2x−1=0.知识点：运用公式法章节：数与式 / 因式分解
