Question

solving an equation graphically
2x+y=-8,x=5y-5

Answer 1

but on the math i got stuck and can't figure out how it came to the conculsion

Answer 2

Plot it very accurate and find the coordinates of the point of intersection.

Answer 3

i mean on the math i got it to this point ( one sec)
2x+y=-8
y=2x-8
then i get stuck

Answer 4

Plot 2 lines:
\(y=-2x-8, \; y=\frac x5-1\)
Can you do this?

Answer 5

no this is my first day of doing these problems trying to perfect the math

Answer 6

http://www.wolframalpha.com/input/?i=Plot [{-2x-8%2Cx%2F5%2B1}%2C{x%2C-7%2C7}]

Answer 7

Copy all the link and paste into the browser.

Answer 8

its taking me to a deadlink

Answer 9

http://www.wolframalpha.com/
Is this a deadlink too?

Answer 10

no

Answer 11

type in the box:
Plot[{-2x-8,x/5+1},{x,-7,7}]

Answer 12

are you doing this on a calculator?

Answer 13

Actually not. But it is easy to plot lines in this way. My picture that you saw higher has lower quality that this one.

Answer 14

the first one i got (-4,8) and the second one i can't get past y=5-x/5

Answer 15

Solution is \((-\frac{45}{11},\frac2{11})\).

Answer 16

k but how did you get there cause i don't even know plz and thanxs

Answer 17

1. If you want to solve it graphically you have to plot both of lines at the same time. And the point, where this lines intersect will be a solution. This is not an accurate method, because you can draw lines perfectly well.
2. If you want an accurate solution, just put an expression for x from the second equation to the first one. you will get:
\(2(5y-5)+y=-8\)
\(10y-10+y=-8\)
\(11y=2\;\Rightarrow\; y=\frac2{11}\)
To find an x put the value of y into one of the equations:
\(2x+\frac2{11}=-8 \; \Rightarrow \; x=-\frac{45}{11}\)

Answer 18

thanxs