x sqd +9x-31=0
2006-08-20 19:21:19 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
x=-11.6589 and
x=+2.6589
Doug
2006-08-20 19:34:47 · answer #1 · answered by doug_donaghue 7 · 0⤊ 0⤋
Solve,
x^2 + 9x - 31 = 0
One method is completing the squares
x^2 + 9x = 31
(x + 9/2)^2 - (9/2)^2 = 31
(x + 9/2)^2 = 31 + 81/4
x + 9/2 = +/- sqrt (205/4)
x = - 4.5 +/- 7.1589
x = -11.6589 or x = 2.6589
2006-08-21 02:46:12 · answer #2 · answered by ideaquest 7 · 0⤊ 0⤋
That is not a quadratic equation since 31 is a prime number.
2006-08-24 22:34:08 · answer #3 · answered by hanna 3 · 0⤊ 0⤋
Since 31 is prime thus the roots will be in points better you check out your equation. However using quadratic formaula -b +- root(D)/2 the solution seems to be:
x=-11.6589 and
x=+2.6589
2006-08-21 02:46:36 · answer #4 · answered by Sandy 2 · 0⤊ 0⤋
x2 + 9x - 31 = 0
u factor it
io think the equation is wrong
because 31 is a prime number so it has no factors
2006-08-21 02:30:34 · answer #5 · answered by -xue- 3 · 0⤊ 0⤋
Xsq + 9x - 31=0
Solution:
x = (-9 +/- sqrt(9sq - 4 * 1 * (-31)) / 2 * 1
= (-9 +/- sqrt(81 + 124)) / 2
= (-9 + sqrt(205)) / 2
= (-9 + 14.3(approx.)) / 2
= 2.65 (approx.)
2006-08-21 04:39:24 · answer #6 · answered by Janice 3 · 0⤊ 0⤋
x^2 + 9x - 31 = 0
x = (-b ± sqrt(b^2 - 4ac))/2a
x = (-9 ± sqrt(9^2 - 4(1)(-31)))/(2(1))
x = (-9 ± sqrt(81 + 124))/2
x = (-9 ± sqrt(205))/2
x = about 2.6589 or about -11.6589
2006-08-21 11:47:11 · answer #7 · answered by Sherman81 6 · 0⤊ 0⤋
in an equation ax^2+bx+c=0
x= [-b+or- sqrt(b^2-4*a*c)] / 2a
2006-08-21 02:28:16 · answer #8 · answered by plstkazn 3 · 0⤊ 0⤋
The quadratic formula
(-B +or- sqrt(B^2-4AC))/2A
where Ax^2+Bx+C=0
x= approx. -11.66 or 2.66
2006-08-21 02:27:00 · answer #9 · answered by Master Maverick 6 · 1⤊ 0⤋