Which dimensions can create only one unique triangle? three angles measuring 25, 65, and 90 three angles measuring 50, 50, and 50 three sides measuring 5 in., 12 in., and 14 in. three sides measuring 4 ft, 8 ft, and 14 ft

When only angles are specified, the sides can be any length, so the triangle is not unique. In any event, the sum of angles must be 180°, so three angles measuring 50° cannot be closed to form a triangle.

Three sides measuring 4, 8, and 14 ft cannot be closed, either, as the long dimension exceeds the sum of the other two. The ends can't meet.

The appropriate choice is the 3rd one ...

... three sides measuring 5 in, 12 in, and 14 in.

x/3-10=8

x/3=18

x=48

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

eventually after a few more steps, your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x