Write a system of equations:

Let first variable is "x " and second variable is " y ".

Given expression is "a number minus twice another number is 4" and

"Three times the first number plus two times second number is  12".

above expression converted in to variables x and y .

"Plus" means addition symbol ()

"Minus" means addition symbol ()

The equation is .

The equation is .

Elimination method:

     ----------(1)

----------(2)

Given equations are,

When the coefficients of a variable and are different,

Adding  (1) and (2) equations will eliminate the variable y.

           (Adding  (1) and (2) equations)

Apply division property of equality: If a = b then .

                        (Divide each side by 4)

                             (Cancel common terms)

                                (Divide: )

Substitute for x in either equation to find y.

                   (Second equation)

                (Substitute )

                   (Multiply: )

Apply commutative property of addition: .

     (Subtract 12 from each side)

                         (Apply additive inverse property: )

                                (Apply additive identity property: )

                            (Divide each side by 2)

                                   (Cancel common terms)                          

The numbers are and .