Find the whole number such that twice its square is 11 more than 21 times the number.​

Let x = the whole number

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From: "twice its square is 11 more than 21 times the original number"

2x^2 = 21x+11

2x^2 - 21x - 11 = 0

Factoring the left:

(2x+1)(x-11) = 0

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Setting each term on the left to zero:

(2x+1) = 0

2x = -1

x = -1/2

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(x-11) = 0

x = 11

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Solution set:

x = {-1/2, 11}

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Since the problem asks for a "whole number" we eliminate the -1/2 leaving us with:

x = 11

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this

x equals 1

step-by-step explanation:

f(4)=f(×)

x=1