Question

In the standard (x,y) coordinate plane, (-1,5) is half-way between (a-9,a) , and (a+3,4a). What is the value of "a"?

Answer 1

do you know the definition of midpoint?

Answer 2

A point on a line segment that divides it into two equal parts;the halfway point of a line segment

Answer 3

how do you express that in geometry?

Answer 4

((x1+x2)/2, (y1+y2)/2))