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

2 thoughts on “the sum of a whole number and twice the square of the number is is 80. find the number?”

1. Answer:

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

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2. 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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