the sum of a whole number and twice the square of the number is is 80. find the number?

Question

the sum of a whole number and twice the square of the number is is 80. find the number?

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Faith 3 months 2021-07-24T12:58:14+00:00 2 Answers 0 views 0

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    0
    2021-07-24T12:59:15+00:00

    Answer:

    Number is 20 which has square as 40 and twice it is 80

    0
    2021-07-24T12:59:21+00:00

    Given – The sum of a whole number and twice the square of the number is 80.

    Find – The whole number.

    Solution – The equation as per mentioned details will be : X + 2x² = 80.

    Taking all the variables to left side, equation will be : 2x² + X -80 = 0

    Solving the formed quadratic equation by Shri Dharacharya formula –

    -b +- ✓(b² – 4*a*c)/2*a.

    Keeping the values in equation-

    X = -1 +- ✓(1² -4*2*80)/2*2

    X = (-1 +- ✓641)/4

    Since x is an whole number, ignoring the negative answer.

    X = 24.3/4

    X = 6.08.

    Rounding the resultant value of X to nearest whole number, X = 6.

    Hence, the nearest whole number is 6.

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