How do i solve with subtraction
4x-y=-12
-6x+5y=-3
2007-02-12 16:26:21 · 4 answers · asked by jaktricky 2 in Education & Reference ➔ Homework Help
multiply the whole top equation by -5...
-20x+5y=60
-6x+5y=-3
then subtract the two equations from each other
-20x - -6x = -14x
5y-5y=0
60 - -3 = 63
which gives us -14x = 63
then just solve for x and put the number back into one of the original equations to get y.
2007-02-12 16:34:38 · answer #1 · answered by Shakespeare, William 4 · 1⤊ 0⤋
The theory of solving with subtraction requires that one of the variables cancels out.
5*(4x-y= -12)
(-20x+5y=60)
- ( -6x +5y=-3)
-----------------------------
-14x+0y=63
x=(-4.5)
y=(-6)
2007-02-12 16:52:31 · answer #2 · answered by Thykon 1 · 0⤊ 0⤋
4x-y=-12
[Add "y" on both sides]
4x=-12+y
[Add "-12" or subtract "-12" from both sides]
4x+12=y
[currently, you have a mx+b equation, slope]
[Division in the same as subtract, just fancier, lol]
Finally Answer can be
y=4x+12
y/4=x+3
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PROBLEM 2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-6x+5y=-3
[Divide everything by "5"]
-6/5x+y=-3/5
[subtract "y" from both sides]
-6/5x=-3/5-y
[Add -3/5 to both sides]
-6/5x+3/5=-y
[Divide everthing by -1]
6/5x-3/5=y
Possible Answer
y=6/5x-3/5
2007-02-12 16:40:22 · answer #3 · answered by Answerz 4 · 0⤊ 0⤋
not sure
2007-02-12 16:34:59 · answer #4 · answered by momof1abc 1 · 0⤊ 0⤋