Sagot :
[tex]\qquad\qquad\huge\underline{{\sf Answer}}♨[/tex]
Let's use section formula ~
[tex]\qquad \sf \dashrightarrow \:x = \dfrac{mx_2 + nx_1}{m + n} [/tex]
[tex]\qquad \sf \dashrightarrow \:y = \dfrac{my_2 + ny_1}{m + n} [/tex]
And since mid point divides a line segment Into two equal parts, m : n = 1 : 1
so, take m = n = 1
[tex]\qquad \sf \dashrightarrow \:x = \dfrac{(1 \times - 1)+(1 \times - 2)}{ 1+ 1} [/tex]
[tex]\qquad \sf \dashrightarrow \:x = \dfrac{- 1- 2}{ 2} [/tex]
[tex]\qquad \sf \dashrightarrow \:x = \dfrac{ - 3}{ 2} [/tex]
Now, let's find y - coordinate ~
[tex]\qquad \sf \dashrightarrow \:y = \dfrac{(1 \times - 5) + (1 \times - 4)}{1 + 1} [/tex]
[tex]\qquad \sf \dashrightarrow \:y = \dfrac{ - 5 - 4}{2} [/tex]
[tex]\qquad \sf \dashrightarrow \:y = \dfrac{ - 9}{2} [/tex]
So, coordinates of midpoint is ~
[tex]\qquad \sf \dashrightarrow \:( - \dfrac{3}{2} ,- \dfrac{9}{2} )[/tex]