this half my grade i cant fail help

Let's see what to do buddy....
[tex]T = b + \frac{d}{2f} \\ [/tex]
Subtract sides b
[tex]T - b = b - b + \frac{d}{2f} \\ [/tex]
Simplification
[tex]T - b = \frac{d}{2f} \\ [/tex]
Multiply sides by 2f
[tex](T - b)(2f) = d[/tex]
So ;
[tex]d =( T - b) \times (2f)[/tex]
We're done but i wanna go one step more...
[tex]d = T \times 2f - b \times 2f[/tex]
[tex]d = 2Tf - 2bf[/tex]
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Hope helped buddy....♥️♥️♥️♥️♥️
Good luck :)