Question

Make the perfect square of
2x^2 + x -1

Answer 1

Answer:

The formula used is=

${ {a}^{2} + 2ab \: + } \: b^{2}$

${ ({2x}^{2} + x - 1)}^{2} \\ = {4x}^{4} + {x}^{2} + 1$

Answer 2

Answer:

x= √3/4 -1/2, x= -√3/4 -1/2

Step-by-step explanation:

To make it perfect square, use completing square method.

2 x^2 + x - 1 =0

Dividing the equation by 2 to make the coefficient of x^2 one

= x^2 + x/2 - 1/2 = 0

Adding 1/4 and subtracting 1/4 in the equation

= (x^2 + 2* x* * 1/2 + 1/4) - 1/4 -1/2 = 0

= (x+ 1/2)²-  (3/4) = 0

or, (x+1/2)² =  3/4

x+ 1/2 = √3/4 or  x+ 1/2 =  -√3/4

or, x= √3/4 -1/2, x= -√3/4 -1/2