Respuesta :
if ∡a and ∡b are complementary angles, that simply means that ∡a + ∡b = 90°.
[tex]\bf \stackrel{\measuredangle a}{x}~~+~~\stackrel{\measuredangle b}{2x+75}~~=~~90\implies 3x=15\implies x=\cfrac{15}{3}\implies \boxed{x=5} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \stackrel{\measuredangle a}{5}~\hspace{7em}\stackrel{\measuredangle b}{2(5)+75}\implies 85[/tex]
a + b = 90
angle a= x°
angle b= (2x+75)°
3x + 75 = 90 subtract 75 from both sides
3x= 15 divide by 3
x=5
a = 5
5+b = 90 subtract 5 from both sides
b = 85