题目计算:(1)4x2⋅(−3x)2(1)4x^{2}\cdot \left(-3x\right)^{2}(1)4x2⋅(−3x)2；(2)(2m−3)(m+5)(2)\left(2m-3\right)\left(m+5\right)(2)(2m−3)(m+5)；(3)(4a3+12a2b−7a3b2)÷4a2(3)(4a^{3}+12a^{2}b-7a^{3}b^{2})\div 4a^{2}(3)(4a3+12a2b−7a3b2)÷4a2；(4)2xy(x2−3y2)−4xy(2x2+y2)(4)2xy(x^{2}-3y^{2})-4xy(2x^{2}+y^{2})(4)2xy(x2−3y2)−4xy(2x2+y2)；(5)(5)(5)先化简,再求值:(x−2)2−(2x+3)(2x−3)+3x(x+2)\left(x-2\right)^{2}-\left(2x+3\right)\left(2x-3\right)+3x\left(x+2\right)(x−2)2−(2x+3)(2x−3)+3x(x+2),其中x=5x=5x=5.知识点：多项式乘多项式章节：数与式 / 整式
