Answer:
18) z + 5 = 4z - 4
3z = 9, so z = 3
z + 5 = 8
The side lengths of this equilateral
triangle are 8 units.
19) 2x + 6.8 = 8x + 1.4
6x = 5.4, so x = .9
2(.9) + 6.8 = 1.8 + 6.8 = 8.6
The congruent side lengths of this
isosceles triangle are 8.6 units.