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Popular Word Problems >

If a number is subtracted from two times its square, the result is twenty-eight. 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 tw o t im es i t s s q u a re, t h e res u lt i s tw e n t y - e i g h t . F in d a ll s u c h n u mb ers .

Solution

The number : 4 or - 3 \frac{1}{2}

Solution steps

Represent the number with

x

A.T.Q.:

2 x^{2} - x = 28

Solve for

x, 2 x^{2} - x = 28 : x = 4, x = - \frac{7}{2}

Convert improper fractions to mixed numbers:

\frac{7}{2} = 3 \frac{1}{2}

The number : 4 or - 3 \frac{1}{2}

Popular Examples

four times the number is decreased by 7 is less than seven less than the number.in 8 years jamie will be three times as old as she is now how old is she now seventy five less than the product of 30 and a number is-225. what is the number?Find the time required for an investment of 5000 dollars to grow to 7600 dollars at an interest rate of 7 percent per year, compounded weekly.15 years from now Maria will be twice as old as Sharon.The current sum of the ages of Maria and Sharon is 42.How old is Sharon right now?