Question 62101
Expand the equation to get 3-8x+16=29, which simplifies to -8x+19=29 when combining like terms.  Now subtract 19 from both sides and get -8x=10 and now divide both sides by -8 to get {{{x=-expr(10/8)}}} which reduces to {{{x=-expr(5/4)}}}.  For the rectangle and triangle problems, you need to submit specific problems to algebra.com