Question

Evaluate the determinant.

Answer 1

\[\left| \frac{ \frac{ 1 }{ 6 } }{ \frac{ -6 }{ 5 } } \frac{ \frac{ 1 }{ 8 } }{ \frac{ 10 }{ 7 } }\right|\]
sorriees
I have no idea how to solve this...please explain?

Answer 2

this doesn't look right... :D

Answer 3

\[\large \left|\begin{matrix}\frac16 &\frac13\\\frac{-6}5&\frac{10}7\end{matrix}\right|\]

Answer 4

oops lol yes...sorryyy /.\

Answer 5

Or was it 1/8?
\[\large \left|\begin{matrix}\frac16 &\frac1{\color{red}8}\\\frac{-6}5&\frac{10}7\end{matrix}\right|\]

Answer 6

I obviously need to work on my checking skills, its 1/8

Answer 7

remember that to do determinants you multiply horizontally in the form:
\[A=\left[\begin{matrix}a & b \\ c & d\end{matrix}\right]\]
\[A=ad-cb\]

Answer 8

What he said ^

Answer 9

So it's just \[\frac{ 1 }{ 8 } x \frac{ -6 }{ 5 }\]

and

\[\frac{ 1 }{ 6 } \times \frac{ 10 }{ 7 }\] ?

but don't I need a common denominator first?

Answer 10

you can just multiply them out straight away.... common denominators are for wusses (and for adding and subtracting HAHA)

Answer 11

I multiply fractions horizontally, correct? Lol I haven't done this in forever so I'm lost

Answer 12

yes, horizontally haha

Answer 13

\[-\frac{ 6 }{ 40 } - \frac{ 10 }{ 42 }\]

Answer 14

o.o did I mess up