## LifeIsADangerousGame Group Title Help with some geometry? one year ago one year ago

If you transform triangle ABC (red triangle) using (x,y)->(y+7, 2x-4). Where would you place point C’? (4,5) I keep getting (12,4) but that isn't right, what am I doing wrong?

2. ParthKohli Group Title

Hmm, $$(x,y) \mapsto (y + 7, 2x - 4)$$. In the same way, $$(4,5) \mapsto (5 + 7, 2(4) - 4)$$

That would be 12,4 wouldn't it? 5 + 7 equals 12 and 2(4) is 8 minus 4 that's 4.

4. ParthKohli Group Title

Good point.

My possible answers are, (4,-4), (11,-12), (3,4), (12,-11)

6. ParthKohli Group Title

Well, there's a thing you're doing wrong there.

7. ParthKohli Group Title

Point $$\rm C$$ is actually $$(4,-4)$$

8. ParthKohli Group Title

Does that make everything better?

With it being (4,-4) I would have the answer of (3,4) I think I'll go with that @ParthKohli