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

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

2021-02-05

Let x be the number.
Eight times the number is 8x8x. 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 $$5+8x=x−21$$. Solving for x gives:
$$5+8x=x−21$$
$$5+7x=−21$$
$$7x=−26$$
$$\displaystyle{x}=−{\frac{{{26}}}{{{7}}}}$$
The number is then $$−\frac{26}{7} ​$$

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