show work thanx
2006-10-12 10:21:28 · 8 answers · asked by yankee_914 1 in Science & Mathematics ➔ Mathematics
Let u=3x-1.
Then you can solve u^2 - 5u - 14 = 0.
This factors nicely into (u-7)(u+2) = 0, so u=7 or u=-2. If you don't see this factorization, you can always use the quadratic formula to find these values.
Since u=3x-1, you can plug these values into this equation to obtain the values of x that solve the original equation.
2006-10-12 10:28:36 · answer #1 · answered by James L 5 · 0⤊ 0⤋
Expanding (3x-1)^2 -5(3x-1)-14=0
9x^2-21x-8 = 0
(3x-8)(3x+1)=0
=> x=8/3 & x=-1/3
2006-10-12 10:30:06 · answer #2 · answered by alam_1209 1 · 0⤊ 0⤋
Let y = 3x -1
y^2 - 5y - 14 = 0
factor
(y-7)(y+2)
y = 7 and y = -2
now take these and plug into first equation to find x:
y = 3x -1
7 = 3x -1
8 = 3x
x = 8/3
y = 3x - 1
-2 = 3x - 1
-1 = 3x
x = -1/3
2006-10-12 10:36:27 · answer #3 · answered by Anonymous · 0⤊ 0⤋
(3x - 1)^2 - 5(3x - 1) - 14 = 0
lets think of this like this
x^2 - 5x - 14 = 0
(x - 7)(x + 2) = 0
x = 7 or -2
or in this case
3x - 1 = 7 or -2
3x = 8 or -1
x = (8/3) or (-1/3)
2006-10-12 16:32:17 · answer #4 · answered by Sherman81 6 · 0⤊ 0⤋
(3x - 1)^2 - 5(3x-1) -14 = 0
(3x-1)(3x -1-5) -14
(3x-1)(3x-6) - 14
(9x^2 -18x -3x +6) - 14
(9x^2 -21x - 8
Factorizing this expression
9x^2 - 24x + 3x - 8
which gives us
(3x - 8)(3x + 1)
2006-10-12 10:43:58 · answer #5 · answered by quark_sa 2 · 0⤊ 0⤋
look first of all u need to know this formula:
(a+b)^2= a^2+2ab+b^2
now:
(3x-1)^2 -5(3x-1)-14=0
(3x-1)^2=9x^2-6x+1
-5(3x-1)=-5*3x+5=-15x+5
9x^2-6x+1-15x+5-14=0
9x^2-21x-8=0
21+/-(root: 21^2+4*8*9)/18
1- (21+27)/18 = 2.66
2- (21-27)/18= -0.33
2006-10-12 11:20:04 · answer #6 · answered by Anonymous · 0⤊ 0⤋
x= 5/12
-(3x-1)^2-5(3x-1)-14=0
(3x-1)^2+15x+5-14=0+14
(3x-1)^2+15x+5=14-5
(3x-1)^2+15x=9
9x-1+15x=9+1
9x+15x=10
24x=10/24
x=5/12
2006-10-12 10:43:48 · answer #7 · answered by ♥KiYa♥ 3 · 0⤊ 1⤋
Hahaha, need someone to do your math homework?
9x-1 -15x+5 -14
-6x-10
Perhaps?
2006-10-12 10:29:42 · answer #8 · answered by S.M. 2 · 0⤊ 1⤋