A1 Determine the value of the parameter $m$ so that the graph of the function $f(x)=(2 m+3) x-(1-2 m)$ intersects the x-axis at 3.
(A) $m=3$
(B) $m=2$
(C) $m=1$
(D) $m=-1$
(E) $m=0$
A1. The condition for the graph to intersect the $x$-axis at $x=3$ is $0=(2 m+3) \cdot 3-(1-2 m)$. In the equation, we remove the parentheses $0=6 m+9-1+2 m$, then we simplify it $0=8 m+8$. We calculate that $m=-1$.