Besides 0, where does the equations y=4x and 2x^2 cross? (no calculator)

Question

amistre64 · Answer

cross what?

amistre64 · Answer

each other...ok  right?

anonymous · Answer

yes, where the two equations cross, I will need to to plug into the bounds of green's theorem

amistre64 · Answer

we want to know where y = y really

and y = 4x   and y = 2x^2

so..... 4x = 2x^2 when?

0 = 2x^2 -4x

0 = 2x(x-2)  ; recall that any number times zero will equal zero.

so either (0)(x-2) = 0

or;  2x(x-2) = 0

2x=0 when x = 0

x-2 = 0 when x = 2

amistre64 · Answer

green has a theorum?

amistre64 · Answer

....im pretty sure your smart enough to catch that :)  2x(0 = 0 is what I meant lol

anonymous · Answer

thanks, I hate forgetting basic factoring and algebra

amistre64 · Answer

it takes practice, it like typing....you can be a pro at it and still mess it up lol

anonymous · Answer

yup thanks, I've been spoiled by a calc and my professor refuses us to ever use on in class