Question

Solve the following system of equations:

-2x + y = 1
-4x + y = -1

Answer 1

do you know how to subtract 2 equations ?
if you know, subtract those 2 equations, and 'y' will get eliminated! :)

Answer 2

won't i have to do the opposite

Answer 3

what does that mean ?
if that means making the sign of 'y' as opposite, so that you can eliminate it, then yes :)
subtracting will make the sign of y opposite.

Answer 4

Can you walk me through

Answer 5

sure, subtracting 2 equations means subtracting left sides and right sides of them
\(\Large (-2x+ y ) - (-4x+y) = 1 - (-1)\)

can you try to simplify that ^ ?

Answer 6

well what i would do is take one of the equations and turing it into y=mx+b form, and then substitute it into the other equation.
so you could change -4x+y=-1 and write it as y=4x-1 then substitute into the other equation so your doing -2x+(4x-1)=1 then just simplify.if you do this correctly you should be left with 2x-1=1. get x by itself, giving you x=1.
plug x back into y=4x-1 and you are left with y=3.
your answer would be Y=3 and X=1

Answer 7

thats using substitution method

Answer 8

and @hartnn i dont get you method

Answer 9

thats called elimination method.
if you observe, 'y' gets eliminated and you directly get the value of x

Answer 10

your way was easiest @hartnn It took me awhile but i got it using both.

Answer 11

i am glad you got it :)

Answer 12

but for equations like that dont you have to find the value for both x and y?

Answer 13

ofcourse!
once you get 'y', use any of the 2 original equations to get the value of x :)

Answer 14

oh, here you got x
then use any of the 2 original equations to get the value of y :)

Answer 15

i see that makes sense. thank you that is easier it seems. again thank you.

Answer 16

and welcome ^_^