Can anyone help me with this? i don’t understand it, thank you.

24

Step-by-step explanation:

It is done by Middle term splitting.

Taking the general equation ax² + bx + c, by middle term splitting, "b" should be splitted such that the numbers either on adding or on subtracting must be equal to "b" and their products must be equal to "a x c".

For example, in the question it's already given that the equation 8x² + bx + c is middle term splitted into 8x² + px + qx + 3.

So, that means "p x q" must be equal to "8 x 3", i.e., 24.

Hope it helps :)