Question

What is the inverse of matrix A, to the nearest tenth?
-2 7
A= 6 -8

Answer 1

Three questions of the same type!!!

For any 2x2 matrix of the form
a b
c d

first find the denominator to be used for each term of the inverse matrix
which is (ad - bc)

so:
a b --> d -b
c d --> -c a

now divide each of the new terms by the denominator you found

so:
-2 7
6 -8

the denominator will be 16 - 42 = -26

and the inverse is
(-8/-26) (-7/-26)
(-6/-26) (-2/-26)

=
(4/13) (7/26)
(3/13) (1/13)

Do the other two questions the same way

Here is a good page to see how to set it up
http://www.cems.uwe.ac.uk/~klhender/espressomaths/mathcentre/Maths_1st_Aid_Kit/5_4.pdf