Question

Choose the expression that represents a quadratic expression. 9x − 2 5x2 + 9x − 1 −2x3 + 8x2 − 7x + 1 x4 − 12x3 + 8x2 − 7x + 1

Answer 1

B. 5x2 + 9x − 1

Explanation:

just took the test

Answer 2

`5 {x}^(2) + 9x - 1`

Explanation:

A quadratic expresion is of the form

`a {x}^(2) + bx + c`

where

`a \\e0`

The give options are:

`9x-2`

`5{x}^(2)+9x - 1`

`-2x^3+8 {x}^(2) -7x +1`

`x^4-12x^3+8 {x}^(2) -7x +1`

From the given options, the only expression which is quadratic is

`5 {x}^(2) + 9x - 1`

where a =5, b=9 and c=-1

Therefore the correct choice is the second option.