The equations are
\
Equation (1)
Equation (2)
Multiply the equation (2) by 2.
\
Equation (3)
Eliminate the variable s by subtracting the Equation (1) from Equation (3)
\
(Subtract the corresponding columns)
Apply division property of equality: if a = b, then
.
(Divide each side by 5)
(Cancel common terms)
(Divide:
)
Substitute
in equation (1).

Apply subtraction property of equality: if a = b, then
.
(Subtract 4 from each side)
Apply commutative property of addition: 

(Apply Additive inverse property:
)
(Apply Additive identity property:
)
(Subtract:
)
Apply division property of equality: if a = b, then
.
(Divide each side by 4)
(Cancel common terms)
(Divide:
)
The solution is 
The solution is
.