Question #97873

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Answer 1 · 2017-01-29T22:19:52

$d=6$

Given: $" "2d-5=7$

Determine the value of $d$

Add $color(magenta)(5)$ to both sides. This turns the 5 on the left of the = into 0

$color(green)(2d-5=7" "->" "2d-5color(magenta)(+5)=7color(magenta)(+5))$

But $-5+5 = 0$ giving:

$" "->" "color(green)(2d+0=12)$

Divide both sides by $color(magenta)(2)$ . This turns the 2 in $2d$ into 1

$" "color(green)( ->" "2/(color(magenta)(2)) xx d=12/(color(magenta)(2))$

But $2/2=1$ giving

$" "color(green)(->" "1xxd=6)$
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$d=6$