Could someone explain how to do 16?

75+(2x-5)=180 (they form a straight angle)

Combine like terms
2x+70=180

Subtract 70 from both sides
2x=110

Divide both sides by 2
x=55

Angle y is the vertical angle of angle (2x-5). Therefore, they are equivalent in terms of degrees.

y= 2x-5
y=2(55)-5
y=110-5
y=105

Final x=55, y=105