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Popular Word Problems >

If a number is subtracted from five times its square, the result is eighteen. Find all such numbers

Solution

I f a n u mb er i s s u b t r a c t e d f ro m f i v e t im es i t s s q u a re, t h e res u lt i s e i g h t ee n . F in d a ll s u c h n u mb ers

Solution

The number : 2 or - 1 \frac{4}{5}

Solution steps

Represent the number with

x

A.T.Q.:

5 x^{2} - x = 18

Solve for

x, 5 x^{2} - x = 18 : x = 2, x = - \frac{9}{5}

Convert improper fractions to mixed numbers:

\frac{9}{5} = 1 \frac{4}{5}

The number : 2 or - 1 \frac{4}{5}

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