Trent Carpenter

2021-02-04

Five more than eight times a number is the same as twenty-one less than a number.

Let x be the number.
Eight times the number is $8x$. Five more than eight times the number is then $5+8x$.
Twenty-one less than the number is $x-21$.
Since five more than eight times the number is the same as twenty-one less than the number, then $5+8x=x-21$. To find x
$5+8x=x-21$
$5+7x=-21$
$7x=-26$
$x=-\frac{26}{7}$
The number is then $-\frac{26}{7}$

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