The sum of any two sides of a triangle must be greater than the third side.
1. (2x+5) + (3x-2) > 6x-7
2x+5+3x-2 > 6x-7
5x+3 > 6x-7
-x > -10
x < 10
2. (2x+5) + (6x-7) > 3x-2
2x+5+6x-7 > 3x-2
8x-2 > 3x-2
5x > -4
x >
3. (3x-2) + (6x-7) > 2x+5
3x-2+6x-7 > 2x+5
9x-9 > 2x+5
7x > 14
x > 2
All three inequalities x < 10, x > , x > 2 must be satisfied
by x.
x > is automatically guaranteed by x > 2, so we can eliminate
that one and we have x < 10 and x > 2 which can be written as
2 < x < 10
Edwin