The given equation is expressed as
5x + 4y = 21
To determine if (1, 4) is a solution of the equation, we would substitute x = 1 and y = 4 into the equation. If we get 21 on the right, it means that (1,4) is a solution. We have
5(1) + 4(4)
5 + 16 = 21
Since we got 21, it means that (1, 4) is a solution of the equation
The answer is Yes
For (3, 1/4), we would substitute x = 3 and y = 1/4 into the equation. It becomes
5(3) + 4(1/4) = 15 + 1 = 16
Since 16 is not equal to 21, (3, 1/4) is not a solution