i have this:
[2 3 ] [7]
[4 5 ] [8] i got the answer: -5.5 and -6
is that correct?
And how do you know when you can solve it?
[2 3 ] [7]
[4 5 ] [8] i got the answer: -5.5 and -6
is that correct?
And how do you know when you can solve it?
-
There are 2 ways. You can write them as equations 2x + 3y = 7 and 4x + 5y = 8 and solve the set (by elimination )
The other way that has to do with matrices is using the inverse. You can find the inverse by the following rule: A = (a b, c d) A^(-1) = 1/(ad -bc) (d -b, -c a). Thus:
A^(-1) = - 1/2 (5 -4, -3 2). Hence if you multiply the inverse with (7, 8) you will have that:
(x,y) = -1/2 (11, -12) = (-5.5,6)
The other way that has to do with matrices is using the inverse. You can find the inverse by the following rule: A = (a b, c d) A^(-1) = 1/(ad -bc) (d -b, -c a). Thus:
A^(-1) = - 1/2 (5 -4, -3 2). Hence if you multiply the inverse with (7, 8) you will have that:
(x,y) = -1/2 (11, -12) = (-5.5,6)