I'm starting to get the hang of the substitution method, until this problem came to sight.... Where do I put 2x in the first equation?
3x-4y=10
y=2x
2007-11-12 09:43:35 · 4 answers · asked by WayCoo 1 in Science & Mathematics ➔ Mathematics
3x - 4(2x) = 10
3x - 8x = 10
- 5x = 10
5x = - 10
x = - 2
y = - 4
2007-11-16 05:14:59 · answer #1 · answered by Como 7 · 0⤊ 1⤋
The substitution method _substitutes _ one variable in terms of another. In your example,
3x-4y=10
y=2x
y is the same thing as 2x. So we can substitute any where we see "y" with "2x". So...
3x - 4(2x) = 10
3x - 8x = 10
I think you can figure it out from there.
2007-11-12 17:49:12 · answer #2 · answered by ultimatelyconfused 2 · 0⤊ 0⤋
First substitute the 2x:
3x-4(2x)=10
Then solve for x:
3x-8x=10
-5x=10
x=-2
Now put that answer in place of x when solving for y:
y=2(-2)
y=-4
2007-11-12 18:20:20 · answer #3 · answered by Molly 2 · 0⤊ 0⤋
Substitute the 2x for the y.
3x - 4(2x) = 10
Then solve for x.
2007-11-12 17:48:39 · answer #4 · answered by jayjay 2 · 0⤊ 0⤋