vertical angles are angles that are across each other at a junction, and therefore equal. That simply means that the other two angles, (2x+25) and (3x-10) are twins, therefore,
[tex] \bf 2x+25=3x-10\implies 25=x-10\implies \boxed{35=x} [/tex]
so that simply means that one of the twins is hmm say 2x + 25, or 2(35)+25 or 95°, so her twin is also 95°, that's 95+95 = 190° taken up.
now angle y has also a twin, and y and her twin take up the rest of a full circle of 360°, namely 360 - 190 = 170°.
since y and her twin take up 170°, that simply means y takes half of that, 170/2 = 85°.
