evaluate the following expression: 4(2,5) - 5(2,-2)

Question

anonymous · Answer

what's the topic?

anonymous · Answer

Trigonometry

anonymous · Answer

so what do the commas mean?

anonymous · Answer

im not sure. I don't remember learning or seeing this through the lesson

anonymous · Answer

okay hang on a second. let me figure this out.

anonymous · Answer

okay, thank you!

anonymous · Answer

do you need the answer or the work?

anonymous · Answer

both would be nice for future reference

anonymous · Answer

i typed it into google and they said that the answer was 10. But I don't know how they got to  it. Sorry. See if anyone else knows the answer. I've never seen a problem like that in my life. Sorry again.:(

anonymous · Answer

Yeah that's the same thing I got when I typed it into Google. Its alright, thanks for trying though

jim_thompson5910 · Answer

sounds like you're working with vectors

4(2,5) - 5(2,-2)

(4*2,4*5) - (5*2,5*(-2))

(8,20) - (10,-10)

(8 -10, 20 -(-10))

(8 -10, 20 +10)

(-2, 30)

anonymous · Answer

nicely done. i never thought of that!

anonymous · Answer

thank you @jim_thompson5910!

jim_thompson5910 · Answer

you're welcome