Algebra Sbornik Zadanii 9 Klass Kuznetsova 16 Izdanie Otvety Now

I'm adding pic of problem in the book, his answer, and the book solution. He's not understanding this one. Help please! I wish he' Facebook·Saxon Math for Homeschoolers

: Working with arithmetic and geometric progressions. algebra sbornik zadanii 9 klass kuznetsova 16 izdanie otvety

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