If one root of the equation $x^2-5x+k=0$ is $2$, find the value of $k$.

Solution

1. Substitute $x=2$ into the equation $x^2-5x+k=0$.
2. This gives $(2{)}^2-5(2)+k=0$.
3. Simplifying the expression, $4 - 10 + k = 0$.
4. Solving for $k$, we get $-6+k=0$, so $k=6$.
5. Hence the answer is (A).