SOLUTION: I need help please!!!! Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this -x + 4y = 0.5 -3x – 6y =

Algebra ->  Linear-equations -> SOLUTION: I need help please!!!! Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this -x + 4y = 0.5 -3x – 6y =       Log On


   

Question 550740: I need help please!!!!
Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this -x + 4y = 0.5 -3x – 6y = 10.5
Found 2 solutions by ankor@dixie-net.com, mananth:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
-x + 4y = 0.5
-3x – 6y = 10.5
:
Multiply the 1st equation by -30, the 2nd equation by 10,
this gets rid of the decimals and sets it up for elimination
:
+30x - 120y = -15
-30x - 60y = 105
-----------------------adding eliminates x, find y
-180y = 90
y = 90%2F%28-180%29
y = -.5
:
Find x, replace y with -.5 in the 2nd original equation
-3x – 6y = 10.5
-3x – 6(-.5) = 10.5
-3x + 3 = 10.5
-3x = 10.5 - 3
-3x = 7.5
x = 7.5%2F%28-3%29
x = -2.5
:
see if these two values x=-.5 and y=-2.5 check out in the 1st equation
-x + 4y = 0.5
-(-2.5) + 4(-.5) = .5
2.5 - 2 = .5 confirms our solution

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
-1 x + 4 y = 0.5 .............1
3 x -6 y = 10.5 .............2
Eliminate y
multiply (1)by 3
Multiply (2) by 2
-3 x 12 y = 1.5
6 x -12 y = 21
Add the two equations
3 x = 22.5
/ 3
x = 7.50
plug value of x in (1)
-1 x + 4 y = 0.5
-7.5 + 4 y = 0.5
4 y = 0.5 + 7.5
4 y = 8
y = 2