To solve for \( a \) such that the point \((a, 3)\) lies on the graph of the equation \( 5x + y = 8 \), follow these steps:
1. Substitute the known value of \( y \) into the equation: Since the point is \((a, 3)\), we know \( y = 3 \).
[tex]\[
5x + 3 = 8
\][/tex]
2. Isolate \( x \): To find \( x \), we need to isolate it on one side of the equation. Subtract 3 from both sides of the equation:
[tex]\[
5x + 3 - 3 = 8 - 3
\][/tex]
Simplifying this gives:
[tex]\[
5x = 5
\][/tex]
3. Solve for \( x \): Now, divide both sides of the equation by 5:
[tex]\[
x = \frac{5}{5}
\][/tex]
Simplifying this gives:
[tex]\[
x = 1
\][/tex]
Therefore, the value of \( a \) is \( 1 \).
So, [tex]\( a = 1 \)[/tex].