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Quadratic equation problem help please!?

0 votes
need some help with a quadratic equation containing an imaginary number:

2x^2-ix+3 = 0

A= 2
B= -i
C= 3

The answer should be:

3/2i, and -i
asked Jun 20, 2014 in ALGEBRA 1 by anonymous

1 Answer

0 votes

The quadratic equation is 2x2 - ix + 3 = 0.

Use quadratic formula to find roots of the related quadratic equation.

Solution, x = [ - b ± √(b2 - 4ac) ]/2a.

Compare the given equation with standard form of quadratic equation : ax2 + bx + c = 0.

a = 2, b = - i, and c = 3.

Solution, x = [ - (- i) ± √((- i)2 - 4(2)(3)) ]/2(2)

= [ i ± √ (i2 - 24) ]/4

Substitute i2 = - 1.

= [ i ± √ (- 1 - 24) ]/4

= [ i ± √(- 25)]/4

Substitute - 1 = i2.

= [ i ± √(i225)]/4

= [ i ± 5i]/4.

⇒ x = [ i + 5i]/4 and x = [ i - 5i]/4

x = 6i/4 and x = - 4i/4

x = 3i/2 and x = - i.

Solution of the quadratic equation is x = 3i/2 and x = - i.

answered Jun 20, 2014 by lilly Expert

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