Choose the expression that represents a quadratic expression. O 6x4 - 5x3 + 3x2 -7x - 8
) 5x3 + 3x2 -7x - 8
O 2x2 + 3x - 1
. 3x - 1

3) 2 + 3x - 1

Step-by-step explanation:

A quadratic expression is an expression involving a squared term

It can be written as y = a + bx + c, where a ≠ 0

// note that here b and c can be equal to 0

1) 6 - 5  + 3  - 7x - 8 is simply incorrect because you can't write in the previously mentioned form. It is a quartic function, since the unknown variable x in forth degree. It can be written as y = a +b +c + dx + e, where a before ≠ 0

2) 5  + 3  - 7x - 8 is simply incorrect because you can't write in the previously mentioned form. It is a cubic function, since the unknown variable x in third degree.

3) 2 + 3x - 1 is correct

4) 3x - 1 is incorrect because there is no squared term. You could also say that here a = 0 and write it as y = 0 *  + 3x - 1. It is also called a linear function because if you'd draw a graph, it would be a line

answer: c.  

step-by-step explanation:

mixtures containing substances that get attracted to magnet can be separated using a magnet. we can separate iron from a mixture of sand and iron, as only iron attracts to the magnet.