Questions on Algebra: Complex Numbers answered by real tutors!

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Question 154734This question is from textbook Algebra structure and method book 1
: 2/3x-7=xThis question is from textbook Algebra structure and method book 1
: 2/3x-7=x
Answer by Alan3354(1444) About Me  (Show Source):
You can put this solution on YOUR website!
2/3x-7=x
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Multiply by 3x
2 - 21x = 3x^2
3x^2 + 21x - 2 = 0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax^2+bx+c=0 (in our case 3x^2+21x+-2 = 0) has the following solutons:

x[12] = (b+-sqrt( b^2-4ac ))/2\a

For these solutions to exist, the discriminant b^2-4ac should not be a negative number.

First, we need to compute the discriminant b^2-4ac: b^2-4ac=(21)^2-4*3*-2=465.

Discriminant d=465 is greater than zero. That means that there are two solutions:  x[12] = (-21+-sqrt( 465 ))/2\a.

x[1] = (-(21)+sqrt( 465 ))/2\3 = 0.0939764421413039
x[2] = (-(21)-sqrt( 465 ))/2\3 = -7.0939764421413

Quadratic expression 3x^2+21x+-2 can be factored:
3x^2+21x+-2 = (x-0.0939764421413039)*(x--7.0939764421413)
Again, the answer is: 0.0939764421413039, -7.0939764421413. Here's your graph:
graph( 500, 500, -10, 10, -20, 20, 3*x^2+21*x+-2 )