SOLUTION: How do you solve the quadratic equation 3x^2-7x+2=0 using formula? I have worked it out the overall square root to -73 however when i type this is my calculator says maths error?

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: How do you solve the quadratic equation 3x^2-7x+2=0 using formula? I have worked it out the overall square root to -73 however when i type this is my calculator says maths error?       Log On


   



Question 312470: How do you solve the quadratic equation 3x^2-7x+2=0 using formula?
I have worked it out the overall square root to -73 however when i type this is my calculator says maths error?
Thanks For Your Help

Found 2 solutions by solver91311, CharlesG2:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


You have two difficulties here.
First is the fact that you are trying to take the square root of a negative number. Remember, is not defined in the real numbers -- no wonder your calculator is pitching a fit! In order to find an approximation of the square root of -73 you need to factor it into two parts, (-1)(73). Use the definition of the imaginary number , that is , to write

But that problem is secondary to the fact that you improperly calculated the value under the radical in the quadratic formula.



For this equation, , , and







Note: -7 times -7 is +49.





or




John


Answer by CharlesG2(834) About Me  (Show Source):
You can put this solution on YOUR website!
"How do you solve the quadratic equation 3x^2-7x+2=0 using formula?
I have worked it out the overall square root to -73 however when i type this is my calculator says maths error?
Thanks For Your Help"
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a = 3, b = -7, c = 2
x+=+%287+%2B-+sqrt%28+49+-+4%2A3%2A2+%29%29%2F%282%2A3%29+
x+=+%287+%2B-+sqrt%28+49+-+24+%29%29%2F6+
x+=+%287+%2B-+sqrt%2825%29%29%2F6+
x+=+%287+%2B-+5%29%2F6+
x1 = (7 + 5)/6 = 12/6 = 2
x2 = (7 - 5)/6 = 2/6 = 1/3
check:
(x - 2)(x - 1/3) = 0 (use FOIL)
x^2 -(1/3)x -2x + 2/3 = 0
3x^2 - x - 6x + 2 = 0 (multiplied both sides by 3)
3x^2 - 7x + 2 = 0
not sure how you got your answer,
but if you taking a square root of a negative number on a calculator
you are going to get an error