Question

What is the solution of this matrix equation?
-Picture below-

Answer 1

@jim_thompson5910 Please help??

Answer 2

step 1) find the inverse of the matrix on the left side

step 2) multiply both sides by the inverse (left multiply) to isolate X

Answer 3

if you forget how to find the inverse of a 2x2 matrix, check out this page

http://www.mathsisfun.com/algebra/matrix-inverse.html

Answer 4

Can you explain how to find an inverse? Matrices are so confusing >_<

Answer 5

have a look at that page and tell me what you think

Answer 6

so it's kind of like cross multiplying?

Answer 7

kind of...

Answer 8

there is a swap that's similar to cross multiplication

Answer 9

Okay, so for step one I got:
1 -4
-2 9

Answer 10

that's the inverse, good job

Answer 11

the inverse of the matrix on the left side

Answer 12

now multiply both sides by this inverse

Answer 13

1 0
0 1 for the left side

3 -18
15 -68 for the right side

correct?

Answer 14

1 0
0 1 for the left side

is correct

Answer 15

the right side is not correct

Answer 16

oh well it would be
1 -4
-2 9
multiplied by
-9 -6
-1 -8

right?

Answer 17

correct

Answer 18

oh I did it the other way around the first time

Answer 19

for each side, the inverse is on the left

Answer 20

so it would be
-5 26
9 -60

Answer 21

matrix multiplication is NOT commutative

ie AB = BA is not true in general

Answer 22

good

Answer 23

oh okay, that's good to know for later! Thank you so much!!

Answer 24

Why the left side? Well if A and B are two matrices such that