Question

What is the answer for x^2+2x+1=9

Answer 1

Answers: x = 2 or x = -4

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Work Shown

`\text{x}^2+2\text{x}+1=9\\\\\text{x}^2+2\text{x}+1-9 = 0\\\\\text{x}^2+2\text{x}-8 = 0\\\\(\text{x}-2)(\text{x}+4) = 0\\\\\text{x}-2 = 0 \ \text{ or } \ \text{x}+4 = 0\\\\\text{x} = 2 \ \text{ or } \ \text{x} = -4`

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Another approach is to use the quadratic formula to solve
`\text{x}^2+2\text{x}-8 = 0`

Plug in a = 1, b = 2, c = -8.

`\text{x} = (-b\pm√(b^2-4ac))/(2a)\\\\\text{x} = (-2\pm√((2)^2-4(1)(-8)))/(2(1))\\\\\text{x} = (-2\pm√(4 + 32))/(2)\\\\\text{x} = (-2\pm√(36))/(2)\\\\\text{x} = (-2\pm6)/(2)\\\\\text{x} = (-2+6)/(2) \ \text{ or } \ \text{x} = (-2-6)/(2)\\\\\text{x} = (4)/(2) \ \text{ or } \ \text{x} = (-8)/(2)\\\\\text{x} = 2 \ \text{ or } \ \text{x} = -4\\\\`