Question

find the root of the quadratic equation x2-9=0

Answer 1

The roots of the quadratic equation x² - 9 = 0 are - 3 & 3

Given : The equation x² - 9 = 0

To find : The roots of the quadratic equation

Solution :

Step 1 of 2 :

Write down the given equation

The given equation is x² - 9 = 0

Step 2 of 2 :

Find the roots

We find the roots by factorisation method as below

$\sf {x}^{2} - 9 = 0$

$\sf \implies {x}^{2} - {3}^{2} = 0$

$\sf \implies (x + 3)(x - 3)= 0$

x + 3 = 0 gives x = - 3

x - 3 = 0 gives x = 3

The roots are - 3 & 3

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Answer 2

Answer:

The roots of the equation are 3, and -3.

Step-by-step explanation:

Given that:-

$x^2-9=0$

To find- The roots of the quadratic equation,

The formula to be used:-

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

where as, a = 1, b = 0, and c = 9

Now, plug all the values in the formula:

$=> x=\frac{-0 \pm \sqrt{0^{2}-4 \cdot 1(-9)}}{2 \cdot 1}$

Simplifying it further, we get

$=> x=\frac{0 \pm \sqrt{0+36}}{2 \cdot 1}$

$=> x=\frac{0 \pm 6}{2 \cdot 1}$

$=> x=\frac{ \pm 6}{2 }$

Now, separating the equations:

$=> x=\frac{ 6}{2 }$

$=> x = 3$

$=> x=\frac{ - 6}{2 }$

$=> x = -3$

Hence, the roots are 3 and -3.