# Identify the factors of x^{2} - 4x - 21 = 0

**Solution :**

Given quadratic equation is:

**x ^{2} - 4x - 21 = 0 is in the form of ax^{2} + bx + c = 0**

Now solving the equation by factorising

x^{2} - 4x - 21 = 0

**For factorising first split the middle term - 4x as - 7x and + 3x as -7x + 3x **

= - 4x and (-7x) (3x) = - 21 x^{2}

⇒ x^{2} - 7x + 3x - 21 = 0

⇒ x(x - 7) + 3(x - 7) = 0

⇒ (x + 3) (x - 7) = 0

**Hence. the factors of x ^{2} - 4x - 21 = 0 are (x + 3) and (x - 7).**

## Identify the factors of x^{2} - 4x - 21 = 0

**Summary:**

The factors of the given quadratic equation x^{2} - 4x - 21 = 0 are (x + 3) and(x - 7).

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