题目计算:(1)(x−1)2+(x−2)(x+3)(1)\left(x-1\right)^{2}+\left(x-2\right)\left(x+3\right)(1)(x−1)2+(x−2)(x+3)；(2){4x+y=7x−12−y3=1(2)\left\{\begin{array}{l}4x+y=7\\ \frac{x-1}{2}-\frac{y}{3}=1\end{array}\right.(2){4x+y=72x−1−3y=1.知识点：解二元一次方程组——代入消元法章节：方程与不等式 / 二元一次方程组
