Question 389536
M[2,-4:-2,5]

These are both valid notations for the determinant of a matrix.
detM[2,-4:-2,5]=M[D,2,-4:-2,5]

The determinant of a 2x2 matrix can be found using the formula M[D,a,b:c,d]=ad-cb
detM[2,-4:-2,5]=(2)(5)-(-2)(-4)

Simplify the determinant.
detM[2,-4:-2,5]=2

The determinant of M[2,-4:-2,5] is 2.
2

 Now, just plug in the 2 to the next question;

2^(-1)

Remove the negative exponent by rewriting 2^(-1) as (1)/(2).  A negative exponent follows the rule a^(-n)=(1)/(a^(n)).
(1)/(2)



And the last question:



2*2^(-1)

Remove the negative exponent by rewriting 2^(-1) as (1)/(2).  A negative exponent follows the rule a^(-n)=(1)/(a^(n)).
2*(1)/(2)

Cancel the common factor of 2 from the first term 2 and the denominator of the second term (1)/(2).
1*1

Multiply 1 by 1 to get 1.
1