11x-65+58=180. The 58 comes from adding 29+29=58. You do this because there are two 29 due to it being an isosceles triangle meaning there are two sides equal.
Add your a like terms
11x-7=180
11x=180+7
11x=187
x=17
Plug the 17 in for 11x-65
11*17-65=122
You can change yourself by adding 29+29+122=180. You know this right because all triangles add to 180. '
