First post, so bear with me lol.
Solve the following system of equations using matrix inversion method:
10x + 14y = 818
8x + 11y = 646
Of course, first order of business is to calculate the determinent, which works out to -2 (10 x 11 - 14 x 8 = -2...unless i calculated it wrong.)
My question is where do I go from here that I have a negative determinent, assuming i calculated it right?
Sorry, one more thing:
The part b to this question is "Suppose now that both right hand-side values are increased by an amount "delta (i.e. triangle..dont have symbol lol). What value of delta causes x to = 35 and what is the value of y at this point?
Here's what i did:
x =  + [-5.5 7] [delta]
y =  [ 4 -5] [ 0 ]
Which of course gives:
23 - 5.5delta = 35
42 + 4delta
-5.5 delta = 12
delta = -2.18
Am I correct? If not, where did I go wrong and where do I go from here?
I interpreted the set-up differently . . .
Suppose now that both right hand-side values are increased by an amount .
What value of makes
and what is the value of at this point?
I think the new equations are: .
We have: . .
The inverse matrix is still: .
Multiply both sides of  by
And we get:.
If , we have: .