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Current time:0:00Total duration:3:35

Reflecting points in the coordinate plane

Video transcript

the point negative 8 comma 5 is reflected across the y-axis plot negative 8 comma 5 and its reflection across the y-axis so first let's plot negative 8 comma 5 so its x-coordinate is negative 8 so I'll just use this one right over here so the x-coordinate is negative 8 and the y-coordinate is 5 so I'll go up 5 so the y-coordinate is 5 right over here you see negative 8 and 5 we've gone 8 to the left because it's negative and then we've gone 5 up because it's a positive 5 so we've plotted negative 8 comma 5 now we have to plot its reflection across the y-axis the y axis and so you can imagine if this was some type of for the some type of lake or something and you were to see its reflection and this is say like the moon you would see its reflection roughly around here you would see an equal distance away from the y axis so you would see it at 8 to the right of the y axis which would be at positive 8 and still fought at a and still 5 above the x axis so that's its reflection right over here this reflection is the point 8 comma 5 let's do a couple more of these the point negative 6 comma negative 7 is reflect this should say reflected across the x axis plot negative 6 comma negative 7 and its reflection across the x axis so negative 6 comma negative 7 so we're going to go 6 to the left of the origin and we're going to go 6 below and we're going to go down 7 so there we go negative 6 comma negative 7 is right there and we are reflecting across the x axis so once again if you imagine that this is some type of a lake or maybe some type of an upside-down lake or a mirror where would we think we see its reflection well its reflection would be the same distance we're reflecting across the x axis so it'd be the same distance but now above the x axis so this was 7 below now we're going to go 7 below above the x axis it's going to be at the same x-coordinate there you have it right over here we reflected this point to right up here because we reflected across the x-axis let's check our answer let's do one more the point B the point B is a reflection of point A across which axis so let's think about this right over here this is at the point negative 6 comma 5 this is at the point negative 5 comma 6 so let's see it doesn't look like it's only one axis if I were to reflect this point across the y-axis it would go all the way to positive 6 5 so it would go all the way right over here so if I reflect a just across the y-axis it would go there and then if I reflected that point across the x-axis then I would go I would end up at 5 below the x-axis at an x coordinate of 6 so to go from A to B you could reflect across the Y and then the X or you could reflect across the X and get you right over here it would get you to negative 6 comma 5 and then reflect across the Y so it's really reflecting across both axes so we would reflect across the x-axis and then the y-axis it would have also been legitimate if we said the Y axis and then the x axis let's check our answer we got it right