If a ordered pair is a solution to the Equation, then it must satisfy the Equation
Let us check the Ordered pairs (4 , 9) and (3 , 2)
Given Equation : 7x - y = 19
Checking whether ordered pair (4 , 9) satisfies :
⇒ 7(4) - 9 = 19
⇒ 28 - 9 = 19
⇒ 28 = 28
⇒ Ordered pair ( 4 , 9) satisfies the Equation
Checking whether (3 , 2) satisfies the Equation :
⇒ 7(3) - 2 = 19
⇒ 21 - 2 = 19
⇒ 19 = 19
⇒ Ordered pair (3 , 2) satisfies the Equation
So, (4 ,9) and (3 ,2) are the Ordered pairs which are solutions to the given Equation.