SOLUTION: Hello everyone! I realize it is stated only one problem per submission, however, there are two problems I worked on and worked on and worked on. Each time I thought I had finally s

Algebra ->  Linear-equations -> SOLUTION: Hello everyone! I realize it is stated only one problem per submission, however, there are two problems I worked on and worked on and worked on. Each time I thought I had finally s      Log On


   

Question 458020: Hello everyone! I realize it is stated only one problem per submission, however, there are two problems I worked on and worked on and worked on. Each time I thought I had finally solved correctly I still ended up wrong on quiz.
I have a test reviewing these types of problems (and others) and would like to understand how to do them correctly prior to taking the test. Any help would be so appreciated!
PROBLEM #1:
Solve the system of equations by graphing. Check your solution.
2x+y=-8
3x-y=3

PROBLEM #2:
Solve the system of equations by graphing. Check your solution.
y=x+3
x+y= -2/5
Thank you!
Found 4 solutions by stanbon, edjones, richwmiller, wilft1:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
PROBLEM #1:
Solve the system of equations by graphing. Check your solution.
Solve each for "y" and graph both on the same set of axes.
----
2x+y=-8
y = -2x-8
You need 2 points to graph the line:
(0,-8) and (-2,-4) will do
---------------------
3x-y=3
y = 3x-3
(0,-3) and (1,0)
---------------------
graph%28400%2C300%2C-10%2C10%2C-10%2C10%2C-2x-8%2C3x-3%29
Solution is the point at which the lines intersect:
Solution: (-1,-6)
-----------------------
Checking:
2x+y = -8
-2-6 = -8
-8=-8
--------------
3x-y = 3
3(-1)-(-6) = 3
-3+6 = 3
3 = 3
=====================
Cheers,
Stan H.
=====================
PROBLEM #2:
Solve the system of equations by graphing. Check your solution.
y=x+3
x+y= -2/5

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
2x+y=-8
3x-y=3
--------add
5x=-5
.
x=-1
y=-6
.
Ed

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
It says to solve by graphing.
Solved by pluggable solver: DESCRIBE a linear EQUATION: slope, intercepts, etc
Equation 3+x+%2B+-1+y+=+3 describes a sloping line. For any
equation ax+by+c = 0, slope is -a%2Fb+=+-3%2F-1.
  • X intercept is found by setting y to 0: ax+by=c becomes ax=c. that means that x = c/a. 3/3 = 1.
  • Y intercept is found by setting x to 0: the equation becomes by=c, and therefore y = c/b. Y intercept is 3/-1 = -3.
  • Slope is -3/-1 = 3.
  • Equation in slope-intercept form: y=3*x+-3.
graph%28+500%2C+500%2C+1-8%2C+1%2B8%2C+-3-8%2C+-3%2B8%2C+3%2Ax%2B-3+%29+

Solved by pluggable solver: DESCRIBE a linear EQUATION: slope, intercepts, etc
Equation 2+x+%2B+1+y+=+-8 describes a sloping line. For any
equation ax+by+c = 0, slope is -a%2Fb+=+-2%2F1.
  • X intercept is found by setting y to 0: ax+by=c becomes ax=c. that means that x = c/a. -8/2 = -4.
  • Y intercept is found by setting x to 0: the equation becomes by=c, and therefore y = c/b. Y intercept is -8/1 = -8.
  • Slope is -2/1 = -2.
  • Equation in slope-intercept form: y=-2*x+-8.
graph%28+500%2C+500%2C+-4-8%2C+-4%2B8%2C+-8-8%2C+-8%2B8%2C+-2%2Ax%2B-8+%29+

Answer by wilft1(217) About Me  (Show Source):
You can put this solution on YOUR website!
problem 1
2x+y=-8
x y
----------
(3, -14)
(5, -18)
(8,-24)

2(3)+y=-8
6+y=-8
-6 -6
y=-14

2(5)+y=-8
10+y=-8
-10 -10
y=-18
2(8)+y=-8
16+y=-8
-16 -16
y=-24
x y
---------
(2, 3)
(4, 9)
(6, 15)
3(2)-y=3
6-y=3
y=3
3(4)-y=3
12-y=3
y=9
3(6)-y=3
18-y=3
y=15
problem 2
x y
--------
(2, 5)
(4, 7)
(6, 9)
real simple on this one
y=x+3
y=2+3
y=4+3
y=6+3


x y
-----------
(2, -12/5)
(4, -22/5)
(-2, 8/5)
x+y=-2/5
2+y=-2/5
10/5+y=-2/5
-10/5 -10/5
y=-12/5

4+y=-2/5
20/5+y=-2/5
-20/5 -20/5
y= -22/5
-2+y=-2/5
-10/5+y=-2/5
+10/5 +10/5
y= 8/5

hope this helps