When we reflect a point across y=x, the x and y coordinates switch out , that is (x,y) becomes (y,x) . SO for point (1,2), on reflection across y=x, (1,2) becomes (2,1) . And when we do reflection across y=-x, (x,y) becomes (-y,-x). Therefore point (2,1) on reflection across y=-x becomes(-1,-2) .
So the final answer is (-1,-2) .
Answer:
D
Step-by-step explanation:
-4(x-7)=36
-4x+28=36
-4x=8
x=-2
Answer:
20 fence posts.
Step-by-step explanation:
Calvin is building a fence. The fence will enclose a 100 square foot area, 10 ft wide by 10 ft long. Calvin can put fence posts 2 feet apart.
Now, if he puts a fence post at each corner of the building, then considering each length of the building there will be
posts along each length.
Now, considering each width of the building there will be
posts (excluding the corner posts) along each width.
Therefore, in total there will be (6 + 6 + 4 + 4) = 20 fence post in the total fence. (Answer)
Similarities: same atomic number
Differences: they have a different number of neutrons