The equations are 2x + 7y = 3 and  x = 1 – y . \ \

2x + 7y = 3        Equation (1)

x = 1 – y             Equation (2)

Since x = 1 – y, substitute 1 – y for x in the first equation.

2(1 – y) + 7y = 3

2 – 2y + 7y = 3          (Distributive property: )

2 + 5y = 3                  (Add: )  

Apply subtractionn property of equality: if a = b then a – c = b – c.

2 + 5y – 2 = 3 – 2      (Subtract 2 from each side)

5y = 1                         (Simplify)

Apply division property of equality: if a = b then 

                    (Divide each side by 5).

                         (Cancel common terms).

Now, find the x value by substituting  in Equation 2.

                   (Cancel common terms).

Write the right hand side equation with common denominator.

                (Least common denominator of 1 and 5 is 5).

Since denominators are same, subtract the numerators over the denominator.

                        (Leat common denominator of 1 and 5 is 5).

The solution is (x , y) = .