The midpoint of a straight fence AB is M(−2, 5). One end of the fence is B(4, −1). Find the other end A.

**Section formula (internal)**:
A point $P$ dividing segment $AB$ in ratio $m:n(P$ closer to A means $m$ smaller) has coordinates:

$P=(\frac{m{x}_2+n{x}_1}{m+n},\frac{m{y}_2+n{y}_1}{m+n})$

Where $A=(x$₁, $y$₁), $B=(x$₂, $y$₂).

**Midpoint** is the special case $m=n:M=(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})$.

**Example**: Find the point dividing $AB$ in ratio 2:3 where $A=(1,5),B=(6,-5).x=\frac{2\cdot 6+3\cdot 1}{5}=\frac{15}{5}=3.y=\frac{2\cdot (-5)+3\cdot 5}{5}=\frac{5}{5}=1$.
Point: (3, 1).