Question

Solve the given equation by the method of completing the squares: x2 + 12x – 45 = 0

Answer 1

x^2 + 12 x - 45 = 0

=> x^2 + 12x =45

add (6)^2 both side

=> x^2 + 12x + (6)^2 = 45 + (6)^2

=> x^2 + 2. (6).x + (6)^2 = 81 =(9)^2

=>(x + 6)^2 = (9)^2

=> (x + 6)^2 -(9)^2 = 0
use formula,
a^2 - b^2 = (a - b)(a + b)

now,
=>(x + 6 -9)(x + 6 + 9)=0

=> x=3 , -15 , hence roots of equation is 3 and -15

Answer 2

Answer: answer is 3;-15