Answer:
(7, 11)
Step-by-step explanation:
If a line segment has endpoints at A([tex]x_1,y_1[/tex]) and B([tex]x_2,y_2[/tex]), the coordinates of the midpoint O(x, y) of the segment AB is given by the formula:
[tex]x=\frac{x_1+x_2}{2}\\\\y=\frac{y_1+y_2}{2}[/tex]
Given the midpoint M(3, 5) of the segment CD with the coordinates of C at (-1, -1). Let the coordinates of D be at ([tex]x_2,y_2[/tex]). Hence:
[tex]x=\frac{x_1+x_2}{2}\\\\ 3=\frac{-1+x_2}{2} \\\\6=-1+x_2\\\\x_2=6+1\\\\x_2=7\\\\y=\frac{y_1+y_2}{2}\\\\ 5=\frac{-1+y_2}{2} \\\\10=-1+y_2\\\\y_2=10+1\\\\y_2=11[/tex]
Hence the coordinates of D is at (7, 11)
