IDQ--Simultaneous Equations

Created by David Landy (Sep 20, 2017).

Solve using substitution. Thanks to Mr. Taylor for encouraging us to replicate his "Increasingly Difficult Questions" inside Graspable Math. See the original at http://taylorda01.weebly.com/uploads/4/2/3/8/42387051/simultaneous_equations_03.pdf, and lots more at http://taylorda01.weebly.com/increasingly-difficult-questions.html