solve the following simultaneous equations using matrices 3x-6y=24 and -4x+5y=-23

Answer 1

Assuming you know how to calculate a determinant, the answer is
x = |24 -6| / |3 -6| = -18/-9 = 2
....|-23 5|/ |-4 5|
You can get y by substitution of x=2 in either equation, or from a separate ratio of determinants.
If you are not familiar with the notation, nor why I chose those numbers, nor how to calculate the determinants, then you need to review the subject. Your textbook should contain that information.

Answer 2

Those are supposed to be square 2 x 2 matrices in numerator and denominator of my previous answer. It is hard to get the type spacing right to align the top and bottom halves. The | | symbols denote the determinant of the matrix.