Asked by Katy
Hi! I need help with this question. Thanks!
Directions: To solve these problems, you need to find the inverses of these 2x2 matrices.
a.) D= [-3 -6
6 12]
b.) C= [2 1
7 3]
Directions: To solve these problems, you need to find the inverses of these 2x2 matrices.
a.) D= [-3 -6
6 12]
b.) C= [2 1
7 3]
Answers
Answered by
Reiny
in general, for
a b
c d
the inverse is
d -b
-c a , where each term is divided by the determinant (ad - bc)
so
-3 -6
6 12 ---->
12 6
-6 -3 , each divided by -36 + 36 or 0
so this does not have an inverse.
for
1 2
7 3
determinant is (3 - 14) or -11
inverse is
-3/11 2/11
7/11 -1/11
a b
c d
the inverse is
d -b
-c a , where each term is divided by the determinant (ad - bc)
so
-3 -6
6 12 ---->
12 6
-6 -3 , each divided by -36 + 36 or 0
so this does not have an inverse.
for
1 2
7 3
determinant is (3 - 14) or -11
inverse is
-3/11 2/11
7/11 -1/11