Question

Form a quadratic equation whose
roots are (3 + √2) and (3 - √2).
(A) x2 - 6x - 7 = 0
(B) x2 + 6x + 7 = 0
(C) x2 + 6x - 7 = 0
(D) x2 - 6x + 7 = 0​

Answer 1

Answer:

Solution:

Completing the square method:

x

2

+6x=7

Adding [

2

1

×coefficient ofx]

2

both sides we get,

x

2

+6x+[

2

1

×6]

2

=7+[

2

1

×6]

2

or, x

2

+6x+3

2

=7+3

2

or, (x+3)

2

=16

or, x+3=

16

or, x+3=±4

or, x=4−3 or x=−4−3

or, x=1 or x=−7