Relax

Respuesta :

GH = 7y + 3 , HI = 3y - 5, GI = 9y + 7

7y + 3 + 3y - 5 = 9y + 7
10y - 2 = 9y + 7
10y - 9y = 7 + 2
y = 9 <===

lets check that..
7(9) + 3 + 3(9) - 5 = 9(9) + 7
63 + 3 + 27 - 5 = 81 + 7
93 - 5 = 81 + 7
88 = 88 (correct)

so yes, y = 9