why we use the variables x and y in math?
142796
becuase this is an A B conversation, so you can C your way out of it.
846806
If you want a visual answer, a function of one variable is graphed by a line, wavy or however.  A function of two variables is graphed by a surface.  Obviously, equations with two variables take more work and effort to make anything out of them, than those with just one.
256883
This is a question containing 2 variables x and y. This can be solved either by knowing the value of one of the variables, or by means of simultaneous equations. (Using another equation containing the same two variables).\n\nThe answer to your current question can only be simplification of the equation.\n\ni.e\n\nxy-4x=1
803959
f(x) =Function of X or (two variables)\ny= a variable\n\nThe differnce of f(x) and y depends on the problem you are dealing with. X & Y could be variables on a graph or they could be given numbers to plug in and solve for. The differnce in x and y variable are just the letter that you are solving for unless there is an equation. If you have a math book it should go into more detail.
202630
people are not here to do your homework:\n\nThis is the definition of a function:\nA variable y is a function of x if a relation between x and y produces exactly one value of y for each value of x.\n\nread it carefully, the answer to your question is quite obvious
77913
Well, you need to know what the variable is equal to to solve. To simplify, if for example you had to devide -1 by x, you would write -1/x.\n\nBy the way, you don't have to start every question with "how in the world." Some more specifics would help though. If you are working on a specific problem, copy it word for word.
1171615
I think this is also the 'trial and error method'\nYou will have an equation where you do not know the value of x.\nKeep on substituting different values of x into the equation until you come up with the right answer.\nIf you are lucky, you may have been told that x lies somewhere between 2 values.\nBest way to do it is to choose a number, get the answer, then choose another number a fair bit larger than the first. If the answer you want is between these 2 values, choose a number about half way between the 2 and so on.
486558
Easiest way to resolve this is to rearrange the equation for either x or y:\n\nx = (10-y)/2\n\ny = 10-2x\n\nSo if you already know y, then you use the first equation, and if you know x, then use the second.\n\nFor example, the first one would require using the second equation: y = 10 - 2 x 5 = 0, therefore first one is (5,0).\n\nThe next one would require using the first equation: x = (10 - 10) / 2 = 0, therefore the second one is (0, 10).
425598
Yes, y=12-x, or x+y = 12 is a linear (no powers) equation in two variables (x, y).\n\nWhen graphed, the equation is a straight line passing through the points (0, 12) and (12, 0)
491343
Equations with one variable can be solved with just that equation for example 2x=4 can be simplified to x=2.\n\nAn equation with two variables cannot be solved purely by itself. For example 4x = 2y can only be simplied to 2x = y. You cannot find the values of x and y without a second equation. If you were given the following two equations 4x = 2y and x + y = 3 then you could use them to calculate x = 1 and y = 2.
152774
I'm not sure if the x is supposed to be the multiplication symbol or a variable.\n\nIf you mean 2*(4*2) or 2(4*2), the result is: 16\n\nIf it is the letter "x", the answer is:\n2x(4*2) = 2x(8) = 16x
1171788
An equation involving x and y.  So called because the x & y axes are at right angles to each other.
747950
It's many years since I did maths but shouldn't there be an = somewhere? And isn't there normally "y" too? I thought it would be fun to stretch my brain for a change but...Am I being obtuse?
718048
x + y = 3\n\nSolve for a variable.  I chose X.\nx+y = 3\n -y    -y\nx = 3 - y\n\nSubstitute the value of X in the first equation.\n2(3-y) + y = 4\nDistribute.\n6-2y+y = 4\nAdd like terms.\n6-y = 4\n-6    -6\n-y = -2\nmultiply by -1.\ny=2\n\nSince you know Y = 2, substitute that back into the second equation that you solved for X with.\nx + y = 3\nX + 2 = 3\n  -2    -2\nX = 1\n\nX = 1\nY = 2
706776
y is a function of x and in a linear way, so one can say that y is a linear function of x,\non the other hand, y=x+5 is a linear equation in 2 variables x and y.\n\nthe difference between function and equation is whether you can write a variable as a function of the other or not: for example:\nx^2 + y^2 =1 is an equation in 2 variables, but it is not a function... or more precisely you cannot get a function from it, since you would need to use the square root (at some point).\n!
596471
X & Y is used to find a point on a graph.  X is the number across, and Y is the number up or down.\n\nThat's all I have.\n\nFYI, ur question is a little vague...
1029923
Understand where the variables in an equation are coming from.  Also what do the variables mean.  Rewrite the equations many times and reread them.  I always write them in a note card and take the note cards with me when I take a bus ride or something like that.  That helps!