Question 910410
x the longest side
{{{x/2 + x +(x-7)  = 78}}} |Multiplying thru by 2 so as all denominators = 1
x + 2x + 2(x-7)  = 156
x + 2x + 2x - 14= 156
5x = 170
x = 34
Sides: 17, 34, 27
and checking..
17 + 34 + 27  = 78