ok so you would do 5x-30+5x=180 to get 10x-30=180 then it would be 10x=210 and x would equal 21
since it appears to be an isoscleles triangle the bottom 2 angles are congruent so the angle on the other side of the auxilary angle would be 5x-30 and since a line is equal to 180 you add 5x-30 to 5x and make it equal to 180 and then solve