Question

Which constant must be added and subtracted to solve the quadratic equation 9 x square + 3 by 4 x minus?

Answer 1

Hi,

Given quadratic equation

9x^2 - 3x/4 - 2 = 0

( 3x )^2 - 2 × 3x x 1/8 - 2 = 0

(3x)^2-2 × (3x) x(1/8) + (1/8)^2 - (1/8)^2

= 2 -----------( 1 )

( 3x - 1/8 )^2 = 2 - ( 1/8 )^2

( 3x - 1/8 )^2 = 2 - 1/ 64

( 3x - 1/8 )^2 = (128 - 1)/ 64

( 3x - 1/8)^2 = 127/ 64

From ( 1 )

Here we added and

subtracted

(1/8)^2 = 1/ 64 to solve the

quadratic

equation by the completing square.

Option B is correct.

I hope this will useful to you.