I need help with these problems please:

Solve by Factoring:

The problem i got is that any combination of number I got that produced -24 didn't add to 6.

Mr F says: Start by writing it as 3(x^2 + 2x - 8) = 0.
And:

Mr F says: Start by writing it as 5(x^2 - 8x - 9) = 0.
And:

Mr F says: This has the form of a perfect square.
Solve the equation.

Mr F says: .
The answers were:

a.

b.

Use the Quadratic Formula to solve the equation.

My solution didn't match the 2 possible answers provided:

and

Mr F says: Show your working.
provided possible answers:

or

Mr F says: Show your working.
I know its kind of alot but I absolutely cannot figure this out! Help is very appreciated