दी गई दो संख्याओं को आपस में बदलने पर, निम्नलिखित में से कौन सा समीकरण सही होगा? 15 और 21

If '+' is interchanged with '-' and '×' is interchanged with '÷', what will come in place of '?' in the following equation? 529 ÷ 23 + 89 - 12 × 9 = ?

By interchanging which two signs will the given equation become correct? 15 - 9 ÷ 6 × 10 + 5 = 25