i forgot what to do when theres two variables
2007-01-10 10:02:20 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
you can't find the exact value of one without a second equation, but you can solve in terms of one.
d = 20 - 4c
and
c= (20-d)/c
then, if you have another equation you can plug in one of the expressions above so you only have one variable and solve. Then, plug that number into the other expression so you can solve for the other one.
2007-01-10 10:34:44 · answer #1 · answered by Susie 2 · 0⤊ 0⤋
divide the 4c and the 20 by 4. you come out with c+d=5 as your answer, and that's as low as you can go I think. Are you trying to solve for a certain variable?
2007-01-10 10:29:00 · answer #2 · answered by Anonymous · 0⤊ 0⤋
You make something up for one of them, then you solve for the other one. The one you invent a number for is called the independent variable. The one you solve for is called the dependent variable.
If you want to reach them both as dependent variables, then you need another equation that relates the same two variables, then solve them simultaneously (play them off against each other) to "eliminate" one of them, solve for the other, than use the other go solve for the one you eliminated.
AMANDA F's answer is wrong!
2007-01-10 10:44:33 · answer #3 · answered by Anonymous · 0⤊ 0⤋
You can't solve an equation in 2 variables. You need to have another equation in c and d.
Usually, there are two equations called simultaneous equations.
2007-01-10 10:36:55 · answer #4 · answered by coolkatt 2 · 0⤊ 0⤋
4c+d=20
4c=20-d
c=(20-d) divided by 4
2007-01-10 10:26:49 · answer #5 · answered by avirothfeld 3 · 0⤊ 0⤋
Which variable do you need to solve for > c or, d?
2007-01-10 11:03:16 · answer #6 · answered by ♪♥Annie♥♪ 6 · 1⤊ 0⤋
4c+d=20
4c=20-d
c=(20-d)/4
OR
d=20-4c
2007-01-10 10:30:39 · answer #7 · answered by hirunisha 2 · 0⤊ 0⤋