SOLUTION: PLEASE HELP. I wanted to put some effort but does not look right. Solve the system of equations by graphing. Then classify the system. 4x-y =20 4x+5y = -28; I substituted

Question 382249: PLEASE HELP. I wanted to put some effort but does not look right.
Solve the system of equations by graphing. Then classify the system.
4x-y =20
4x+5y = -28;
I substituted for x with 5 in the first equation: 4 (5)-y = 20-5; y = 15; (5,15)
I then substituted -9 for y in the same equation: 4x-(-9) = 20; 4x+9-9=20-9; x = 2.75; (2.75, -9).
Second equation
4x+5y = -28; I substituted 0 for x; 4(0)+5y = -28; y = -5.6. The first point is (0,-5.6).
I then substituted -9 for y in the same equation; 4x+5(-9) = -38; 4x+45-45 = -38-45; 4x=7; Divide by 4; x = 1.8; Second points (1.8, -9)
They are consistent because of one solution and are independent as well?? help.
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
Solve the system of equations by graphing. Then classify the system.
4x-y =20
4x+5y = -28;
I substituted for x with 5 in the first equation: 4 (5)-y = 20-5; y = 15; (5,15)
---------------
4x-y = 20
4*5 - y = 20
y = 0
(5,0) is better.
---------------------
I then substituted -9 for y in the same equation: 4x-(-9) = 20; 4x+9-9=20-9; x = 2.75; (2.75,-9)
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-------------------
Second equation
4x+5y = -28; I substituted 0 for x; 4(0)+5y = -28; y = -5.6. The first point is (0,-5.6)
-----------------
I then substituted -9 for y in the same equation; 4x+5(-9) = -38; 4x+45-45 = -38-45; 4x=7; Divide by 4; x = 1.8; Second points (1.8,-9)
--------------
4x - 45 = -28
4x = 17
x = 4.25
(4.25,-9) not (1.8,-9)
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They are consistent because of one solution and are independent as well?? help.
-------------
They're consistent and independent.
If you plot the points and graph them, you'll see they intersect.
-------------
dl the FREE graph software at
http://www.padowan.dk

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