Question

The vertices of a triangle are P(4, 1), Q(2, -8) and R(-8, 1). What are the vertices of the image reflected across the y-axis?
A. P'(4, -1), Q'(2, 8), and R(-8, 1).
B. P'(-4, 1), Q'(-2, -8), and R'(8, 1)
C. P'(-4, -1), Q'(-2, 8), and R(8, -1)
D. P'(4, 1), Q'(2, -8), and R'(-8, 1)

Answer 1

(x,y) -> (-x,y)

you just invert the x axis..

Answer 2

so p(4 ,1) becomes (-4,1) etc etc..

Answer 3

@hughfuve oh.. would it be B?

Answer 4

looks right.. sorry I meant invert x coordinate.. not 'x-axis'.. but yeah after you invert all the x coord's you get b

Answer 5

http://www.virtualnerd.com/pre-algebra/geometry/transformations-symmetry/reflecting-figures/reflect-y-axis-using-coordinates

Answer 6

@khurramshahzad @hughfuve I can't help but be confused, it could easily be B or C in my eyes

Answer 7

its B

Answer 8

if it were C, then both the x and y would need to be inverted, and as you are only reflecting over y-axis then you only invert the x coord's

Answer 9

@khurramshahzad @hughfuve Your link was very helpful- thank you to the both of you!