May i get the answers to these 2 multiple choice questions ?

6)
AB=5x-7
BC=3x+1
AC=4x

30=AB+BC+AC
30=5x-7+3x+1+4x
30=12x-6
36=12x
3=x

AB=5*3-7=15-7=8
BC=3*3+1=10
AC=4*3=12

so the side lengths in order are
AB(8), BC (10),AC (12)

now just take the angles opposite of the side:

C, A, B which is the last option

7)
To be a triangle every single die has to be smaller than the other 2 added together

6, 23, 11: 6+11<23 -> can't be a triangle
10, 15, 24: 10+15>24, 10+24>15, 15+24>10 -> it is a triangle
22, 6, 6: 6+6<22 -> can't be a triangle
15, 9, 24: 15+9=24 (but not larger!) -> can't be a triangle

so 10, 15, 24 is the solution