how to make a texbox active when insert with text?

Question

Hi Team

 

I want to make my Next button active, only when a user select both radio-button and textbox. i want to know jquery side of things, with my following logic i have below.

<div class="col-sm-3">
@Html.RadioButtonFor(m => m.CourseAdmin.LoginID, "LoginID")
<label for="LoginID" class="col-form-label">LoginID</label>
</div>
<div class="col-sm-3">
@Html.RadioButtonFor(m => m.CourseAdmin.SIS_ID, "SIS_ID")
<label for="SIS_ID" class="col-form-label">SIS_ID</label>
</div>
<div class="col-sm-12">
@Html.TextAreaFor(m => m.eNtsaAdmin.eNtsaTextAreaDisc, new { @class = "form-control", style = " font-weight: bold; width:450px" })
</div>
;div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Next</button>