Thread: inverse matrix

i have to write an equation involving an inverse matrix and solve for a, b and c.

so far i've got to

(9 -3 1) (a) (28)
(16 4 1) (b) = (-7)
(49 7 1) (c) (38)

if anyone could help me i would appreciate it a lot as I am really stuck

Hello gbooker

Originally Posted by gbooker

i have to write an equation involving an inverse matrix and solve for a, b and c.

so far i've got to

(9 -3 1) (a) (28)
(16 4 1) (b) = (-7)
(49 7 1) (c) (38)

if anyone could help me i would appreciate it a lot as I am really stuck

Find the inverse of the matrix $\displaystyle \begin{pmatrix}9&-3&1\\16&4&1\\49&7&1\end{pmatrix}$, using the method shown, for instance, here.

When you multiply on the left of each side by this inverse matrix, the LHS becomes $\displaystyle \begin{pmatrix}a\\b\\c\end{pmatrix}$, and the RHS will give (when you complete the multiplication) the solutions you want.

Can you complete it now?

Grandad