BRAINLIEST FOR EXPLANATION (my own question) SO when you have a point on a graph, say it's at (-3,7), and you have to graph the dot after a rotation of 90 degrees counterclockwise around the origin, how would you know what to do?
So I know it is (x, y)--> (-y, x), but having the dot as (-7,3) wouldn't work if you followed that equation. Am I doing it right? If not, how would you apply that 'equation' to (-3,7)?

(-7, -3)

Step-by-step explanation:

So the formula is (x, y) --> (-y, x) for a 90 degrees counterclockwise rotation.

To apply this formula to (-3,7), first identify which is the x-coordinate and which is the y-coordinate.

x-coordinate is -3 & y-coordinate is 7

Then you literally just substitute it into the formula like so:

(-y, x) -->(-(7), (-3)) --> (-7, -3)

Try to put parantheses around the coordinate when substituting to prevent confusion & incorrect negative signs.

Hope it helps and good luck (●'◡'●)

(-7,-3)

Step-by-step explanation:

You could read (x,y)->(-y,x) as if I have the point (x,y), the image point is (opposite of y,x).

So shorthand the rule is just saying

(x,y)->(opposite of y, x)

(-3,7)->(-7,-3)

A few more examples:

(5,7)->(-7,5)

(-5,7)->(-7,-5)

(-5,-7)->(7-,5)

(5,-7)->(7,5)

This whole explanation comes down to reading-u as opposite of u.

Opposite just means to change the sign.

Another way to read -u is -1×u.

Example:

Q: evaluate -u if u=8

A: -8

Why? -u means -1×u or opposite or u. Take your pick in reading it. It's the same meaning just different ways of reading. -1×8=-8 or the opposite or 8 is -8.

Example:

Q: evaluate -u if u=-8

A: 8

Why? -u means -1×u or opposite or u. Take your pick in reading it. It's the same meaning just different ways of reading. -1×-8=8 or the opposite or -8 is 8.