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Solve x2 = 12x – 15 by completing the square. Which is the solution set of the equation? (negative 6 minus StartRoot 51 EndRoot comma negative 6 + StartRoot 51 EndRoot) (negative 6 minus StartRoot 21 EndRoot comma negative 6 + StartRoot 21 EndRoot) (6 minus StartRoot 51 EndRoot comma 6 + StartRoot 51 EndRoot) (6 minus StartRoot 21 EndRoot comma 6 + StartRoot 21 EndRoot)

Answer :

luisejr77

Answer:

LAST OPTION: [tex](6-\sqrt{21},6+\sqrt{21})[/tex]

Step-by-step explanation:

1. Subtract [tex]12x[/tex] from both sides of the equation:

[tex]x^2-12x= 12x- 15-12x\\\\x^2-12x=-15[/tex]

2. Since [tex]b=12[/tex]:

[tex](\frac{b}{2})^2=(\frac{12}{2})^2=(6)^2[/tex]

3. Now can complete the square. Add [tex](6)^2[/tex] to both sides of the equation:

[tex]x^2-12x+6^2=-15+6^2[/tex]

4. Simplifying:

[tex](x-6)^2=21[/tex]

5. Solve for "x":

[tex]\sqrt{(x-6)^2}=\±\sqrt{21}\\\\x-6=\±\sqrt{21}\\\\x=6\±\sqrt{21}\\\\x_1=6+\sqrt{21}\\\\x_2=6-\sqrt{21}[/tex]

6. The solution set is:

[tex](6-\sqrt{21},6+\sqrt{21})[/tex]

regimike

Answer:

the answer is d

Step-by-step explanation:

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