Step 1

Given:

The system of equations are,

\(3x+y=28...(1)\)

\(-x+3y=4...(2)\)

The objective is to find the solution of the coordinates (x,y) and multiply them.

Step 2

The system of equations can be solved by multiplying the equation (2) by 3.

\(3x+y=28\)

\(-3x+9y=12\)

On solving the above two equations for y,

\(10y=40\)

\(\displaystyle{y}={\frac{{{40}}}{{{10}}}}\)

\(y=4\)

Step 3

Substitute the value of y in (2) to find the value of x.

\(-x+3y=4\)

\(-x+3(4)=4\)

\(-x+12=4\)

\(-x=4-12\)

\(x=-4+12\)

\(x=8\)

Thus, the solution of coordinates is (8,4)

Multiplication of x and y is,

\(x \cdot y=8 \cdot 4\)

\(x \cdot y=32\)

Hence, multiplication of the coordinates is 32.