Solve for x. x^2 = 5x + 2
2006-11-22 14:16:38 · 5 answers · asked by George F 1 in Science & Mathematics ➔ Mathematics
x^2-5x-2=0
use the quadratic formula
[5 +/- sqrt(25-4*1*-2)]/2
[5 +/- sqrt(25+ 8)]/2
I distributed the 1/2...easier to type
5/2 +/-sqrt33/2
2006-11-22 14:22:38 · answer #1 · answered by mom 7 · 0⤊ 1⤋
This is a good equation to work out by completing the square. To do this, take the following steps:
1. Move everything but the constant to one side of the equation:
x^2 - 5x = 2
2. Take half of the coefficient of the x-term, and square it. Add this square to both sides of the equation:
x^2 -5x + 6.25 = 2 + 6.25 (-2.5^2 = 6.25)
3. Convert the left side to a square (x + the number you just squared):
(x - 2.5)^2 = 8.25
4. Square-root both sides, remembering the "±" on the right-hand side. Simplify as necessary:
x - 2.5 = ±(sqrt)8.25
5. Solve for x
x = 2.5 ±(sqrt)8.25
Remember that the "±" means that you have two answers, not one.
2006-11-22 22:26:07 · answer #2 · answered by bgdddymtty 3 · 0⤊ 2⤋
x^2 = 5x + 2
x^2 - 5x - 2 = 0
x = (-b ± sqrt(b^2 - 4ac))/(2a)
x = (-(-5) ± sqrt((-5)^2 - 4(1)(-2)))/(2(1))
x = (5 ± sqrt(25 + 8))/2
x = (5 ± sqrt(33))/2
x = (1/2)(5 ± sqrt(33))
2006-11-23 00:02:03 · answer #3 · answered by Sherman81 6 · 0⤊ 0⤋
x = plus or minus the square root of (5x+2).
2006-11-22 22:25:32 · answer #4 · answered by Cassi 2 · 0⤊ 2⤋
By using the quadratic formula
2006-11-22 22:24:31 · answer #5 · answered by BBTech 2 · 0⤊ 3⤋