Could I get some Algebra II help? :)?

Question

Find the coordinates of Q given that M is the midpoint of PQ.

P(0,0), M(2, -4)

Answer 1

Let Q coordinates be (x1, y1)
Midpoint formula is given by (x, y) = ((x1+x2)/2, (y1+y2)/2)
(2, -4) = ((x1+0)/2, (y1+0)/2)
(2, -4) = (x1/2, y1/2)
x1/2 = 2 and y1 = -4
x1 = 2 * 2 =4, y1 = -4 * 2 = -8
Q = (4, -8)