题目已知A=2a2+3ab−2a−1A=2a^{2}+3ab-2a-1A=2a2+3ab−2a−1,B=−a2+ab+2B=-a^{2}+ab+2B=−a2+ab+2.化简:4A−(3A−2B)4A-\left(3A-2B\right)4A−(3A−2B).知识点：代数式求值、整式加减运算法则章节：未标注
