Question

If 5 times of a positive whole number is less by 3 than twice of its square, then let us determine the number​

Answer 1

Answer: 3 is the answer

Let the no. be x

5 times of a positive whole number= 5x

is, = ,less by 3 than twice of its square= $2x^{2}-3$

5x+3= $2x^{2}$

$2x^{2} -5x-3$

By middle term factorizing,

Sum= -5 ( Coefficient of x)

Product= -6( Product of coefficient of $x^{2}$ and the constant, i.e., -3×2)

$2x^{2}-6x+x-3=0\\=(2x^{2} -6x)+(x-3)=0\\=2x(x-3)+1(x-3)=0 \\=(2x+1)(x-3)=0\\= 2x+1=0, : x=\frac{-1}{2} \\x-3=0\\x=3$

Since x is a whole number, it cannot be -1/2.

X=3

That is, 3 is the whole number whose 5 times is less by 3 than twice its square.