Is the answer Prime???
2007-10-22 09:52:56 · 4 answers · asked by LeeBee 3 in Science & Mathematics ➔ Mathematics
x² + 5= 85
x² = 80
x = ± √80
x = ± √(16 * 5)
x = ± 4√5
x ≈ ± 8.94427...
There are two answers, the positive and negative square root of 80. The answer is irrational and can therefore not be a prime number.
Even if you copied this wrong and meant that for this to be sqrt(81), the answer is ±9 which again is not prime.
2007-10-22 09:56:32 · answer #1 · answered by Puzzling 7 · 0⤊ 0⤋
Let the number be x
so
x^2+5=85
x^2=85-5
x^2=80
x= 8.94427191
2007-10-22 09:57:59 · answer #2 · answered by Siva 5 · 0⤊ 0⤋
x^2 + 5 = 85
x^2 = 80
x = 屉(80)
= ±4â5
2007-10-22 09:55:28 · answer #3 · answered by de4th 4 · 0⤊ 0⤋
x^2 + 5 = 85
x^2 = 80
x = +/- sqrt(80) = 8.94, -8.94
2007-10-22 09:55:57 · answer #4 · answered by mathguru 3 · 0⤊ 0⤋