0.45(d-1.2)+0.67=5.53

0.45(d-1.2)+0.67=5.53

use distributive property

0.45d - 0.54 + 0.67 = 5.53

now combine like terms (0.54 + 0.67)

0.45d - 1.21 = 5.53

add 1.21 on both sides

0.45d = 6.74

now divide by 0.45 on both sides

d = 14.9777777778

which rounds to

d = 15