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Which equations have no real solution but have two complex solutions?

3x^2-5x=-8 2x^2=6x-5 12x=9x^2+4 -x^2-10x=34

Respuesta :

Answer:

First option:  [tex]3x^2-5x=-8[/tex]

Second option: [tex]2x^2=6x-5[/tex]

Fourth option: [tex]-x^2-10x=34[/tex]

Step-by-step explanation:

Rewrite each equation in the form [tex]ax^2+bx+c=0[/tex] and then use the Discriminant formula for each equation. This is:

[tex]D=b^2-4ac[/tex]

1) For [tex]3x^2-5x=-8[/tex]:

 [tex]3x^2-5x+8=0[/tex]

Then:

[tex]D=(-5)^2-4(3)(8)=-71[/tex]

Since [tex]D<0[/tex] this equation has no real solutions, but has two complex solutions.

2) For [tex]2x^2=6x-5[/tex]:

 [tex]2x^2-6x+5=0[/tex]

Then:

[tex]D=(-6)^2-4(2)(5)=-4[/tex]

Since [tex]D<0[/tex] this equation has no real solutions, but has two complex solutions.

3) For [tex]12x=9x^2+4 [/tex]:

 [tex]9x^2-12x+4=0 [/tex]

Then:

[tex]D=(-12)^2-4(9)(4)=0[/tex]

Since [tex]D=0[/tex] this equation has one real solution.

4) For [tex]-x^2-10x=34[/tex]:

 [tex]-x^2-10x-34=0 [/tex]

Then:

[tex]D=(-10)^2-4(-1)(-34)=-36[/tex]

Since [tex]D<0[/tex], this equation has no real solutions, but has two complex solutions.

Answer:

First option:  

Second option:

Fourth option:

Step-by-step explanation: