Answer:
d=1
Explanation:
distribute 0.5 through the parentheses
3.5d+2=7-1.5d
move variable to the left-hand side and change its sign
3.5d+1.5d+2=7
move constant to the right-hand side and change its sign
3.5d+1.5d=7-2
collect all like terms
5d=7-2
subtract the numbers
5d=5
divide both sides
d=1