Question 164178
Let:
the angle = x
so the angle's complement = 90 - x


90 - x = 4x - 15
<=> 90 + 15 = 4x + x
<=> 105 = 5x
<=> x = 105/5
<=> x = 21

so the angle = 21 degrees
the angle's complement = 90 - 21 = 69 degrees