SOLUTION: What is the steps for this linear Systems of Equation below. Solve each system by substitution. 1. 5x-y= 1 -5x+y=-3 2. x+2y=-3 -3x+4y=-21 3. 2x+y=22 -8x

Algebra ->  College  -> Linear Algebra -> SOLUTION: What is the steps for this linear Systems of Equation below. Solve each system by substitution. 1. 5x-y= 1 -5x+y=-3 2. x+2y=-3 -3x+4y=-21 3. 2x+y=22 -8x      Log On


   

Question 930051: What is the steps for this linear Systems of Equation below.
Solve each system by substitution.
1. 5x-y= 1
-5x+y=-3

2. x+2y=-3
-3x+4y=-21
3. 2x+y=22
-8x+7y=0
4. -8x+4y=-20
x+y=10
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
1. 5x-y=+1....eq.1
-5x%2By=-3....eq.2
________________
5x-y=+1....eq.1 solve for y
5x-1=+y........substitute in eq.2
-5x%2B5x-1=-3....eq.2
-cross%285x%29%2Bcross%285x%29-1=-3
-1=-3=> sins -1=-3 is not true, there are no solutions and the system is inconsistent and lines are parallel

+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+5x-1%2C5x-3%29+

2. x%2B2y=-3........eq.1
-3x%2B4y=-21.......eq.2
___________________
x%2B2y=-3........eq.1 solve for x
x=-2y-3......substitute in eq.2
-3%28-2y-3%29%2B4y=-21.......eq.2 and solve for y
6y%2B9%2B4y=-21
10y=-21-9
10y=-30
y=-30%2F10
y=-3
go to x=-2y-3 substitute -3 for y and solve for x

x=-2%28-3%29-3
x=-2%28-3%29-3
x=6-3
x=3
intersection point is: (3,-3)





3. 2x%2By=22....eq.1
-8x%2B7y=0....eq.2
___________________
2x%2By=22....eq.1 solve for y
y=22-2x...............substitute in eq.2
-8x%2B7%2822-2x%29=0....eq.2....... solve for x
-8x%2B154-14x=0
154-22x=0
154=22x
154%2F22=x
x=7
go to y=22-2x substitute 7 for x and solve for y
y=22-2%2A7
y=22-14
y=8
intersection point is: (7,8)

+graph%28+600%2C+600%2C+-10%2C+15%2C+-10%2C+15%2C+22-2x%2C%288%2F7%29x%29+


4. -8x%2B4y=-20..........eq.1
x%2By=10.............eq.2
__________________________________
x%2By=10......eq.2 solve for y
y=10-x....substitute in eq.1

-8x%2B4%2810-x%29=-20..........eq.1...solve for x
-8x%2B40-4x=-20
-12x%2B40=-20
20%2B40=12x
60=12x
60%2F12=x
x=5
go to y=10-x plug in value for x
y=10-5
y=5
intersection point is: (5,5)

+graph%28+600%2C+600%2C+-10%2C+15%2C+-10%2C+15%2C+10-x%2C2x-5%29+