题目下列运算正确的是( )A.2a+3b=5ab2a+3b=5ab2a+3b=5abB.5b2−b2=45b^{2}-b^{2}=45b2−b2=4C.7x3−6x2=x7x^{3}-6x^{2}=x7x3−6x2=xD.2xy−2yx=02xy-2yx=02xy−2yx=0知识点:绝对值的性质、整式的混合运算、非负数的性质:偶次方章节:未标注