1.0 video Lesson 25 Solving a System of Equations by Substitution 960 540 iPlayerHD https://iplayerhd.com <iframe src="//iplayerhd.com/player/video/93564116-0103-479b-a7fd-d06821f6afe7?cbartype=over" allowtransparency="true" frameborder="0" scrolling="no" allowfullscreen mozallowfullscreen webkitallowfullscreen oallowfullscreen msallowfullscreen width="960" height="540"></iframe>