Como se resolve passo a passo a equação (d-1)² / d² = 25%?

25%=25/100

(d-1)²/d²=25%
(d-1)²/d²=25/100
(d-1)²/d²=1/4
(d-1).(d-1)/d²=1/4
(d²-2d+1)/d²=1/4
d²-2d+1=d²/4
4d²-8d+4=d²
4d²-8d+4=d²
4d²-8d+4-d²=0
3d²-8d+4=0
d²-8d/3+4/3=0/3
d²-2.4d/3+4/3=0
d²-2.4d/3=-4/3
d²-2.4d/3+16/9=-4/3+16/9
(d-4/3)²=-12/9+16/9
(d-4/3)²=4/9
(d-4/3)²=4/9
d-4/3=±√(4/9)
d=±√(4/9)+4/3

d=+√(4/9)+4/3=+2/3+4/3=6/3
d=-√(4/9)+4/3=-2/3+4/3=2/3​