use using elimination method..thank you..God bless..God loves YOU!
2007-11-26 13:20:24 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
3x - 4y = 21
4x - y = 5
Step 1: Multiply bottom equation by 4 and top equation by -1. You get
-3x + 4y = -21
12x - 4y = -20
--------------------- Now, "add"
9x + 0 = -41
9x = -41
x = -(41/9)
x = -9.56
Step 2: Plug in your x into any of the equations above. I will use 4x - y = 5
4(-9.56) - y = 5
y = -18.22 - 5
y = -23.22
Hope I helped!
God Bless! :-)
2007-11-29 03:08:27 · answer #1 · answered by Jacob F 5 · 0⤊ 0⤋
ok so first you multiply (4x-y=5) by 4 so you can get 16x-4y=20. You do this so you can then subtract 2 from 1, or 1 from 2. so then the x value would be -1/15, then all you do is sub in that into the first or second equation to get y. hope that helped a little
2007-11-26 13:32:13 · answer #2 · answered by June C 2 · 0⤊ 0⤋
3x - 4y = 21 3x - 4y = 21
4(4x - y) = 4(5) equals -16x - 4y = 20
then it will be
-13x = 1
x = -1/13
and now substitute into one of the first two equations
3(-1/13) - 4y = 21
-4y = 21(-13/3) equals to -4y = -91 which is
y = 22.75
so the written solution would be
(-1/13, 22.75) or x = -1/13 and y = 22.75
2007-11-26 13:35:35 · answer #3 · answered by P.A.T.H. 2 · 0⤊ 0⤋
If your solving for X the awnser is -(1/13) but Y=4.962 i think that is correct anyway hope that helps
2007-11-26 13:31:40 · answer #4 · answered by creede_horse_lover 2 · 0⤊ 0⤋
3x-4y=21
4x-y=5
-y=-4x+5
-1(-y)=-1(-4x+5)
y=4x-5
3x-4(4x-5)=21
3x-16x+20=21
-13x+20=21
-13x=1
x=-1/13
4(-1/13)-y=5
-4/13-y=5
-y=5 4/13
y=-5 4/13=-69/13
2007-11-26 13:45:51 · answer #5 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋