Solving $2x + y = 8,\; 3x - 2y = 5$ by substitution, the value of $x$ is —

From $2x + y = 8$ we get $y = 8 - 2x$; substituting into $3x - 2y = 5$ gives $3x - 2(8 - 2x) = 5$, so $7x = 21$ and $x = 3$.