Algebra Points: Solve the system by graphing?

Question

x+y= -13
-2x+y=8

The answer must be in a form similar to: (#, #) for example (–2, –5) OR (7, –3) BUT neither examples is the correct answer for this particular problem I was just giving a form example

Answer 1

Solve this simultaneously.

x+y=-13 --->(1)
-2x+y=8 --->(2)

Use elimination, and multiply (1) by -1, giving

-x-y=13

Add the two new equations, (2) and the equation just above, giving

-x-y=13
-2x+y=8

-3x=21

Therefore x=-7
Substitute the X back in, as 7, into equation (2)

-7+y=-13
y=-13+6

Therefore y=-6

Your final answer is (-7,-6)

Answer 2

here you want to solve for y & put in form y=mx+b. Where m is number in front of x & b is the number by itself. when you solve for both of these guys you get y=-x-13 & y=2x+8; since you want to solve by graphing. b is where the line hits the y axis and m is slope ( slope is rise over run so 2 is up 2 over 1) graph the two lines and the point where they hit will be solution.

Answer 3

x + y = -13
-2x + y = 8

x + y = -13
y = -x - 13

-2x + y = 8
y = 2x + 8

y = -x - 13
y = 2x + 8

For graphs, go to http://www.calculator.com/calcs/GCalc.html

type in -x - 13, 2x + 8, click Trace On, and you will get (-7,-6) to be your answer.

Answer 4

from x+y=-13 you get x=-y-13
you use that in the second equation and you get: -2(-y-13)=8
which leads to: 2y+26=8
then 2y=-18
which is y=-9
you replace that in the first equation and it leads to x=-4
the solution is (-4,-9)

Answer 5

(-7,-6)

Answer 6

(-7,-6)

Answer 7

(-7,-6)

Answer 8

i hope i'm not helping you cheat or anything, but here's the answer i got using substitution: (-7,-6)

Answer 9

(-7, -6)

Answer 10

(-7, -6)