JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<button id="explanation-btn" class="btn" data-exp="explation-1" data-mess='["✖ explanation hidden","✓ explanation shown"]'>✓ explanation shown</button>

<span class="explanation explation-1">объяснение к примеру 1</span>

<button id="explanation-btn" class="btn" data-exp="explation-2" data-mess='["✖ explanation hidden","✓ explanation shown"]'>✓ explanation shown</button>

<span class="explanation explation-2">объяснение к примеру 2</span>

CSS

.explanation{
  display: none;
}

JavaScript

$(function(){
	$(document).on('click', '.btn', function(){
      $('.explanation').hide();
      $('.'+$(this).data('exp')).show();
  })
})