A = 4x + 10
B = x + 80
C = 5x - 10
(4x + 10) + (x + 80) = 5x - 10
5x + 90 = 5x - 10
On a scalene triangle, all the sides have a different measurement so this is scalene trianlge
Well, we need to know theory of the triangle.
From theory we know that a scalene triangle has all its sides different as we have here ( A = 4x + 10, B = x + 80, C = 5x - 10)
An isosceles triangle has 2 sides with the same measurement, somenthing thta does not happen here.
In an equilateral triangle all the sides measure the same, this is not the case.