As per question,
Let the sides be:
a = first side
b = second side
c = third side
As one side is seven inches more than first side,
b = 7 + a
As the third side is four inches less than three times the fiest, so,
c = 3a - 4
As perimeter is 28 inches,
a + b + c = 28
Now solving for sides,
[tex]a = a \\ = > b = 7 + a \\ = > c = 3a - 4[/tex]
So,
[tex]a + b + c = 28 \\ = > a + (7 + a) + (3a - 4) = 28 \\ = > a + 7 + a + 3a - 4 = 28 \\ = > a + a + 3a + 7 - 4 = 28 \\ = > 5a + 3 = 28[/tex]
Now subtract,
5a = 25
=> a = 25÷5
=> a = 5
Now as we got value o lengrh of first side, substitute it to the remaining sides.
=> b = 7 + a
=> b = 7 + 5
=> b = 12
And finally,
c = 3a - 4
=> c = 3×5 - 4
=> c = 15 - 4
=> c = 11
Therefore, the three sides are 5 inches, 12 inches and 11 inches
