plsss help for brainlist !!!!!!!!!

Answer:
[tex]d=2Q-c[/tex]
Step-by-step explanation:
[tex]Q=\frac{c+d}{2}[/tex]
⇒ Switch sides:-
[tex]\frac{c+d}{2}=Q[/tex]
⇒ Multiply both sides by 2:-
[tex]\frac{2\left(c+d\right)}{2}=2Q[/tex]
[tex]c+d=2[/tex]
⇒ Subtract c from both sides:-
[tex]c+d-c=2Q-c[/tex]
[tex]d=2Q-c[/tex]
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