The value of x in the equation is [tex]x = \frac{(7 - r) }{A}[/tex]
Solving for [tex]x[/tex] in the equation gives : [tex]\frac{(7 - r)}{A}[/tex]
[tex]Ax + r = 7[/tex]
Subtract r from both sides in other to isolate [tex]Ax[/tex]
[tex]Ax + r - r = 7 - r[/tex]
[tex]Ax = 7 - r[/tex]
Divide both sides by A in other to isolate x;
[tex]\frac{Ax}{A} = \frac{(7 - r)}{A}[/tex]
Hence, [tex]x = \frac{(7 - r) }{A}[/tex]
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