题目

As we all know, advertisements use p________ language and exciting pictures to encourage people to buy their products. 答案：persuasive对于实数a、b、c、d，我们规定一种新运算：.abcd.=ad-bc，例如：.2345.=2×5-3×4=-2，根据这一规则，当.x-3y1.=49，.2y-1x.=63时，（1）求14xy2的立方根；（2）求yx+xy的值．