Question 450415: Use 0, 1, 2, 3, 4 to substitute for x in the formula x2-x+41; see if prime number occurs then find a number for x that when substituted in the formula yields a composite number.
Answer by Edwin McCravy(20060)   (Show Source):
You can put this solution on YOUR website! Use 0, 1, 2, 3, 4 to substitute for x in the formula x²-x+41; see if prime number occurs then find a number for x that when substituted in the formula yields a composite number.
x x²- x + 41 prime?
0 0²- 0 + 41 = 41 yes
1 1²- 1 + 41 = 41 yes
2 2²- 2 + 41 = 43 yes
3 3²- 3 + 41 = 47 yes
4 4²- 4 + 41 = 53 yes
It's obvious that when 41 is substituted for
x, the middle term will cancel the last
term leaving 41² which is composite.
So when x = 41, x²- x + 41 = 41²- 41 + 41 = 41² = 1681, not prime.
Edwin
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