Factorise x2-2x-8

Given

x2-2x-8

Find out

We need to factories and find the factors of the given quadratic equation

Solution

x2-2x-8

Let us try factorizing this polynomial using splitting the middle term method.

Factoring polynomials by splitting the middle term. Let us assume that the equation is in the form ax2 + bx + c

In this technique we need to find two numbers ‘a’ and ‘b’ such that a + b = -2 and ab = -8

On solving this we obtain, a = -4 and b = 2

Thus, the above expression can be written as:

x2-2x-8

= x2−4x+2x−8
= x(x−4)+2(x−4)

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

x-4=0, x+2=0

x=4 and x= -2

Answer

Thus, x-4 and x+2 are the factors of the polynomial x2-2x-8.

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