Question

7. Use the quadratic formula to find the solution(s). x² + 2x - 8 = 0​

Answer 1

Hey there!

Use the quadratic formula to find the solution(s). x² + 2x - 8 = 0

• Answer :

x = -4 or x = 2 ✅

• Explanation :

Quadratic formula : ax² + bx + c = 0 where a ≠ 0

The number of real-number solutions (roots) is determined by the discriminant (b² - 4ac) :

• If b² - 4ac > 0 , There are 2 real-number solutions

• If b² - 4ac = 0 , There is 1 real-number solution.

• If b² - 4ac < 0 , There is no real-number solution.

The roots of the equation are determined by the following calculation:

$x = \frac{ - b \pm \sqrt{ {b}^{2} - 4ac } }{2a}$

Here, we have :

• a = 1
• b = 2
• c = -8

1) Calculate the discriminant :

b² - 4ac ⇔ 2² - 4(1)(-8) ⇔ 4 - (-32) ⇔ 36

b² - 4ac = 36 > 0 ; The equation admits two real-number solutions

2) Calculate the roots of the equation:

▪️ (1)

$x_1 = \frac{ - b - \sqrt{ {b}^{2} - 4ac} }{2a} \\ \\ x_1 = \frac{ - 2 - \sqrt{36} }{2(1) } \\ \\ x_1 = \frac{ - 2 - 6}{2} \\ \\ x_1 = \frac{ - 8}{2} \\ \\ \blue{\boxed{\red{x_1 = -4}}}$

▪️ (2)

$x_2 = \frac{ - b + \sqrt{ {b}^{2} - 4ac } }{2a} \\ \\ x_2 = \frac{ - 2 + \sqrt{36} }{2(1)} \\ \\ x_2 = \frac{ - 2 + 6}{2} \\ \\ x_2 = \frac{4}{2} \\ \\ \red{\boxed{\blue{x_2 = 2}}}$

>> Therefore, your answers are x = -4 or x = 2.

Learn more about quadratic equations:

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Answer 2

Answer:

x = 2, - 4

Step-by-step explanation:

The factors of 8 are:

1, 8

2, 4

You can combine 2 and 4 to create 2.

( x - 2 ) ( x + 4 ) = 0

0 can either be x - 2 or x + 4

Therefore, x = 2 or - 4