I think that says
[tex] 5 + 1.5(2d - 1) = 0.5[/tex]
Multiplying both sides by 2 to clear the decimals,
[tex]10 + 3(2d -1) = 1[/tex]
[tex]10 + 6d - 3 = 1[/tex]
[tex]6d = 1 + 3 - 10[/tex]
[tex]6d = -6[/tex]
[tex]d = -6 / 6[/tex]
[tex] d = -1[/tex]
Answer: d = -1
Check: 5 + 1.5(2(-1)-1) = 5 + 1.5(-3) = 5 - 4.5 = 0.5 checks, good
