Write x2 - 2x - 3 = 0 in the form (x - a)2 = b, where a and b are integers
Solution:
Given equation is x2 - 2x - 3 = 0
Given quadratic equation can be written in the form (x - a)2 = b by following steps:
Take the coefficient of the middle term (-2) and divide it by 2
Then square the result.
Add this number into the equation right after the middle term
Subtract this number after the last term.
Take the middle term and divide by 2……………..-2/2 = -1
Then square the result ……. (-1)2 = 1
Add this number into the equation right after the middle term ……
let us proceed accordingly,
x2 - 2x + 1 - 3 - 1 = 0
⇒ x2 - 2x + 1 = 4
LHS term is in the form of x2 - 2 × x × 1 + 12
= a2 - 2ab +b2
But by using standard formula:
a2 - 2ab + b2 = (a - b)2
⇒x2 - 2 × x × 1 + 12 = (x - 1)2
Therefore
x2 - 2x + 1 = 4
⇒ (x - 1)2 = 4.
Write x2 - 2x - 3 = 0 in the form (x - a)2 = b, where a and b are integers
Summary:
The equation x2 - 2x - 3 = 0 in the form (x - a)2 = b can be written as (x - 1)2 = 4.
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