Question

x + 2y - z = -1
x - 4y - z = -4
2x - 2y + 3z = 15

Answer 1

solve using matrices

Answer 2

http://www.mathportal.org/calculators/system-of-equations-solver/system-3x3.php Heres a website that will solve your 3 system equation let me know if you can access it to double-check your answer.

Answer 3

I dont understand the explanation it gave

Answer 4

Sorry @cookiimonster27 did you get it? Sorry my typing came out weird... Did you put in your equation, click, and then solve using Cramers rule??

Answer 5

I checked it but it doesnt make any sense let me try again

Answer 6

Still doesn't make sense?

Answer 7

@cookiimonster27 do you still need help or do you get it?

Answer 8

\(\large\tt \color{black}{

\left(
\begin{array}{ccc}
1 & 2 & -1 \\
1 & -4 & -1 \\
2 & -2 & 3 \end{array}
\right)
\times
\left(
\begin{array}{ccc}
x \\
y \\
z \end{array}
\right)=\left(
\begin{array}{ccc}
-1 \\
-4 \\
15 \end{array}
\right)}\)

Answer 9

\(\large\tt \color{black}{

[A][X]=[B]}\)

\(\large\tt \color{black}{ [X]=[A^{-1}][B]}\)

Answer 10

U have to find inverse of
\(\large\tt \color{black}{A=\left(
\begin{array}{ccc}
1 & 2 & -1 \\
1 & -4 & -1 \\
2 & -2 & 3 \end{array}
\right),A^{-1}=?}\)

Answer 11

and multiply it into \(\large\tt \color{black}{[B]=\left(
\begin{array}{ccc}
-1 \\
-4 \\
15 \end{array}
\right)}\)

Answer 12

then u will get \(\large\tt \color{black}{[X]=\left(
\begin{array}{ccc}
? \\
? \\
? \end{array}
\right)}\)

Answer 13

here are two methods to find the inverse
http://www.mathsisfun.com/algebra/matrix-inverse-row-operations-gauss-jordan.html
http://www.mathsisfun.com/algebra/matrix-inverse-minors-cofactors-adjugate.html