Answer:
8<x<33/2
Explanation:
A+B+C=180 ==> all three angles of a triangle=180 degrees
Let's say A=2x+1, B=3x-7. Solve for C:
2x+1 + 3x-7 + C=180
2x+3x+1-7+C=180 ==> join like terms
5x-6+C=180
5(8)-6+C=180 ==> substitute 8 for x
40-6+C=180 ==> simplify
34+C=180
34-34+C=180-34
C=146
5x+C=186
5x-5x+C=186-5x
C=186-5x
a+3x-7=180 ==> these two angles from a straight line (A is separate from a)
2x+1 + 3x-7 + C=180
a+3x-7=2x+1 + 3x-7 + C
a=2x+1 + C ==> subtract 3x-7 from both sides
a=2x+1 + 146 ==> substitute 146 for C
a=2x+147
a<180 ==> a can't be 180 degrees since a equals 180 minus an angle(C).
2x+147<180
2x+147-147<180-147
2x<33
2x/2<33/2
8<x<33/2