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What number must you add to complete the square? x^2+8x=9

2 Answers

1 vote
  • x²+8x+9

We know

  • (a+b)²=a²+2ab+b²

To get 2ab satisfied

  • 2ab=8x
  • 2x(b)=8x
  • b=4
  • b²=16

16 must be added on both sides to get (x+4)²

User Chuky Pedro
by
7.5k points
5 votes


\huge\textsf{Hey there!}


\mathsf{x^2 + 8x = 9}


\large\textsf{SUBTRACT 9 to BOTH SIDES}


\mathsf{x^2 + 8x - 9 = 9 - 9}


\mathsf{x^2 + 8x - 9 = 0}


\large\textsf{FACTOR the LEFT SIDE of the EQUATION}


\mathsf{(x - 1)(x + 9) = 0}


\large\textsf{SET the FACTORS to EQUAL 0}


\mathsf{x - 1 = 0 \ OR \ x + 9 = 0}


\large\textsf{Simplify above and you have your answer to the question above (also}\\\large\textsf{known as the results for your x-values)}


\boxed{\boxed{\large\textsf{Answer: \huge \bf x = 1 or x = -9}}}\huge\checkmark



\large\textsf{But, your overall answer should be:}


\huge\boxed{\textbf{ADD \underline{16} to both sides}}


\large\textsf{Because, you had to break down x}\mathsf{^2}\large\textsf{ to (x + 4)(x + 4) or you could}\\\large\textsf{simply say (x + 2)}\mathsf{^2.}


\large\textsf{Good luck on your assignment and enjoy your day!}

~
\frak{Amphitrite1040:)}

User David Jarvis
by
7.7k points

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