Answer:
The coordinates of point D are (7,11)
Step-by-step explanation:
we know that
The formula to calculate the midpoint between two points is equal to
[tex]M(\frac{x1+x2}{2},\frac{y1+y2}{2})[/tex]
In this problem we have
[tex]M=(3,5)\\C(x1,y1)=(-1,-1)\\D(x2,y2)=?[/tex]
substitute the given values
[tex](3,5)=(\frac{-1+x2}{2},\frac{-1+y2}{2})[/tex]
Solve for x2
[tex]\frac{-1+x2}{2}=3[/tex] ---> [tex]-1+x2=6[/tex] --->[tex]x2=6+1=7[/tex]
Solve for y2
[tex]\frac{-1+y2}{2}=5[/tex] ---> [tex]-1+y2=10[/tex] ---> [tex]y2=10+1=11[/tex]
therefore
The coordinates of point D are (7,11)
