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

Answer:

$5 {x}^{2} + 9x - 1$

Step-by-step explanation:

A quadratic expresion is of the form

$a {x}^{2} + bx + c$

where

$a \ne0$

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.