Question

If D_x = $-$ 18 and D = 3 are the values of the determinant for certain simultaneous equation in x and y, find x.

Answer 1

We know that

$$\begin{gathered} x=\frac{{\mathrm{D}}_{\mathrm{x}}}{\mathrm{D}} \\ \Rightarrow x=\frac{-18}{3} \\ \therefore x=-6 \end{gathered}$$