Question

matrix{{0, 1, -1}, {2, 1, 3}, {1, 1, 1}} matrix{{1, -1, x}} matrix{{0}, {1}, {1}}=0

Find the value of x

Don't give me the direct answer. Please tell me how to go about this. Draw in your notebook and then solve

Answer 1

Your matrix notation does not distinguish rows from columns, which is critical in matrices.
The best possible interpretation I get is:

a11 a12 a13
a21 a22 a23
a31 a32 a33
multiplied by
b1
b2
b3
to give
c1 c2 c3
which is then multiplied by another
d1
d2
d3
to give
e=0

So multiply rows of a to the column b to give c, for example:
c1=a11*b1+a12*b2+a13*b3
and similarly for the other rows.
Same for e:
e=c1*d1+c2*d2+c3*d3

Through the multiplication, you will preserve the value of x, and equate the value of e to zero to solve for x.