Question

X^2-8x+9
find x using the quadratic formula

Answer 1

`x = 4 \pm \sqrt7`

Explanation:

Hello!

Standard form of a Quadratic:
`ax^2 + bx + c= 0`

Given the Equation:
`x^2 -8x+9=0`

• a = 1
• b = -8
• c = 9

Quadratic Formula:
`x = (-b \pm √(b^2 - 4ac))/(2a)\\`

Solve by substituting the values into the Quadratic Formula.

Solve for x

• 
  `x = (-b \pm √(b^2 - 4ac))/(2a)\\`
• 
  `x = (-(-8) \pm √((-8)^2 - 4(1)(9)))/(2(1))\\`
• 
  `x = (8 \pm √(64 - 36))/(2)\\`
• 
  `x = (8 \pm √(28))/(2)\\`
• 
  `x = (8 \pm 2√(7))/(2)\\`
• 
  `x = 4 \pm \sqrt7`

The solution to the quadratic is
`x = 4 \pm \sqrt7`.