Question

Angle Sum Theorem, thank you so much for the help, in advance!​

Answer 1

$y + x = 180° \\ \Leftrightarrow y = 180° - x = 180° - (180° - 30° - 25°) = 30° + 25° = 55°$

Answer 2

sum of the 3 angles of a triangle = 180°

x +25+30 = 180°

x = 180- 55 = 125°

Now angle x + angle y = 180°( supplementary angle)

so put the value of x in the equation, we have

125 + y = 180°

y = 180 -125

y = 55°