The author of the question...sucks !
The drawing is very poor because it shows that it’s an equilateral triangle but in the same time they made it confusing with using the degree sign on the variables..
Very confusing but the best way to do it is
Y+2x+1=180
Y=179-2x
Z+2x-1=180
Z= 181-2x
We found the previous but knowing that a straight line gives us 180
After that we equate all angles in the triangle to 180 (crazy eh?! Also definition of a triangle all angles make up 180)
X+179-2X+181-2X=180
-3x=180-181-179
X=60
Which gives us Y=59 and Z=61 from the equation we created in the beginning.
Fingers crossed it’s correct. Double check my math !