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lorasvet [3.4K]
3 years ago
9

Solve the equation for all values of x by completing the square. x^2+8x=9

Mathematics
1 answer:
SpyIntel [72]3 years ago
5 0

(*)\qquad(a+b)^2=a^2+2ab+b^2\\\\x^2+8x=9\\\\x^2+2\cdot x\cdot4=9\ \ \ \ |+4^2\\\\\underbrace{x^2+2\cdot x\cdot4+4^2}_{(*)}=9+4^2\\\\(x+4)^2=25\to x+4=\pm\sqrt{25}\\\\x+4=-5\ \vee\ x+4=5\ \ \ \ \ |-4\\\\x=-9\ \vee\ x=1

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Answer:

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Step-by-step explanation:

To factor x^2 -x -2, you look for factors of -2 that have a sum of -1:

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Then these are the constants in the binomial factors:

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_____

<em>Comment on the question</em>

The fact that x^2 +3x -4 is modeled with algebra tiles seems to be irrelevant to the question that is actually asked.

4 0
2 years ago
Solve for u.
STALIN [3.7K]

Answer:

5u-15=10 |+15

5u=25 |:5

u=5

The solution is 25

I hope it helps

have anice day

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