Answer:
Midpoint is ( Average of x’s, Average of y’s )
1 = (x + 7)/2
2 = x + 7, x = - 5
and - 1 = (y + (-4))/2
so - 2 = y - 4 and y = 2
Pt B = (- 5, 2)
Expand
x^2+3x-10=18
minus 18 both sides
x^2+3x-28=0
find what 2 numbers mutiply to -28 and add to 3
7 and -3
(x+7)(x-3)=0
set each to zero
x+7=0
x=-7
x-3=0
x=3
x=-7 and 3
I think it is .8 i could be wrong i’m not sure