bgehin60 bgehin60
  • 04-06-2020
  • Mathematics
contestada

If 4 is a solution to x^2+bx-12=0, then b=?

Respuesta :

Isa0811
Isa0811 Isa0811
  • 04-06-2020

Answer:

b = -1

Step-by-step explanation:

First plug in 4 for each x:

[tex]x^2+bx-12=0\\(4)^2+b(4)-12=0[/tex]

Then simplify by multiplying out what you can with 4:

[tex](4)^2+b(4)-12=0\\16+4b-12=0[/tex]

After simplify further by combining like terms:

[tex]16+4b-12=0\\4b +4=0[/tex]

Then isolate b on one side by subtracting 4 from each side:

[tex]4b+4=0\\(-4)+4b+4=0+(-4)\\4b=-4[/tex]

Finally isolate b further by dividing each side by 4 to get b alone and find the answer:

[tex]4b=-4\\\frac{4b}{4}=\frac{-4}{4} \\ b=-1[/tex]

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