SOLUTION: Hi please help :) Determine the value(s) of x such that: A= [x,2,1] B= [6,5,-6] [5,-2,1] [-6,-7,1] C= [x] [-1] [-2] So the actual question becomes A*B*C=0 and i need to

Algebra ->  Matrices-and-determiminant -> SOLUTION: Hi please help :) Determine the value(s) of x such that: A= [x,2,1] B= [6,5,-6] [5,-2,1] [-6,-7,1] C= [x] [-1] [-2] So the actual question becomes A*B*C=0 and i need to      Log On


   



Question 1058051: Hi please help :)
Determine the value(s) of x such that:
A=
[x,2,1]
B=
[6,5,-6]
[5,-2,1]
[-6,-7,1]
C=
[x]
[-1]
[-2]
So the actual question becomes A*B*C=0 and i need to determine the value(s) of x Thanks so much!

Answer by solve_for_x(190) About Me  (Show Source):
You can put this solution on YOUR website!
Multiply the three matrices together to get:



6x^2 + 4x - 5x + 11 + 12x - 6 = 0

6x^2 + 11x + 5 = 0

(6x + 5)(x + 1) = 0

x = -5/6, x = -1