I'm trying to solve this matrix but need help.

1 2 -9 -8
0 1 7 -3
0 0 1 7

my choice of answers are;
a -2, -11, 6
b 159, -52, 7
c -8, -3, 7
d 21, 46, 7

Question

I'm trying to solve this matrix but need help.

1 2 -9   -8
0 1   7   -3
0 0   1     7

my choice of answers are;
a  -2, -11, 6
b  159, -52, 7
c   -8, -3, 7
d   21, 46, 7

owlfred · Answer

Hoot! You just asked your first question! Hang tight while I find people to answer it for you. You can thank people who give you good answers by clicking the 'Good Answer' button on the right!

amistre64 · Answer

im guessing b at sight

anonymous · Answer

what do you mean "solve" it? do you mean find the determinant? do you mean find the eigenvalues?

anonymous · Answer

oh, i see. a system of equations.

amistre64 · Answer

you pretty much work it up from the bottom; that 1,7 means teh last value is = to 7

amistre64 · Answer

1 7 , -3  means 1 +7(7) = -3;  the second so 1 = -52

amistre64 · Answer

1 2 -8, -8 then means:

1 +2(-52) -9(7) = -8

amistre64 · Answer

and i bet that ends up 1 = 159

anonymous · Answer

Thanks,    this stuff is hard for this old mind to get a handle on.

amistre64 · Answer

$$\begin{array}c
x&y&z&|&=\
1&2& -9&|& -8\
 0& 1& 7& |&-3\
 0& 0& 1& |&7
\end{array}$$