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Question 1201411: i have been looking for one fucking person who can tell me what the hell "y" is. i have went to khan academy. i went to microsoft mathsolver. i went to every corner of the earth to find what y means. and i cant find out what it means. y = mx + b
i cant understand how to solve it if im missing a variable. is it the y value on the graph? is it the y variable? WHO KNOWS BECAUSE I DONT.
Found 4 solutions by Theo, math_tutor2020, ikleyn, josgarithmetic:
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! y is the dependent variable in that equation.
x is the independent variable.
the eqution is y = mx + b
that's the equation of a straight line.
if you graph that equation, you will find that the x is the value of the horizontal movement on the graph and the y is the value of the vertical movement on the graph.
m is the slope
b is the y-intercept.
an example:
y = 2x - 10
the slope is 2.
what that says is that the value of y goes up 2 units as the value of x goes up 1 unit.
the y-intercept is -10
the y-intercept is the value of y when the value of x is equal to 0.
here's the graph.
don't get hung up on the variable name.
any name could be used.
the equation could have been a = mb + c
a is the dependent variable
b is the independent variable
c is the constant term.
the x is used because most graph have an x and a y axis.
the x axis is the horizontal axis.
he y axis is the vertical axis.
so, for graphing purposes, it's useful to give the dependent variable the name of y and the independent variable the name of x.
in functional notation, the equation would be shown as f(x) = mx + b
you wouldn't necessaily be able to graph it as such using graphing software.
for graphing purposes, you would then say let y = f(x) and graph the equation of y = mx + b, naturally with some value of m and some value of b.
i don't know if this answer your question.
if so, be happy.
if not, let me know what else might confuse you about it.
in the equation of y = 2x - 10, you would assign the value to x and then solve for y.
that makes x the independent variable and y the dependent variable, because you choose the value of x and the value of y is dependent on the equation.
for example, if x = 5, then y = 2x - 10 becomes y = 10 - 10 which makes y = 0.
Answer by math_tutor2020(3817)  (Show Source):
You can put this solution on YOUR website!
The y is a variable.
Specifically it's the output variable or dependent variable.
It depends on what the input x would be.
Example:
x = number of hours a person works
y = total amount of money they have in their bank account
Let's say the person already has $20
We'll also say the person has an hourly wage of $13 an hour.
The equation would be: y = 13x+20
We can think of it like starting with 20, then adding on 13x to get 20+13x
Then that flips to 13x+20
Therefore, in total they have y = 13x+20 dollars after all is said and done.
Why is this useful? We can quickly figure out how much money they have in their bank account.
All we need to know is how many hours they worked.- If the person worked x = 2 hours, then they have y = 13x+20 = 13*2+20 = 26+20 = 46 dollars.
- If the person worked x = 3 hours, then they have y = 13x+20 = 13*3+20 = 39+20 = 59 dollars.
- If the person worked x = 4 hours, then they have y = 13x+20 = 13*4+20 = 52+20 = 72 dollars.
And so on.
Each x and y pair can then be plotted as a point on a grid. Plot two points to draw a line through them. A graph like this is often useful in presentations to the boss (so they can see if the company is making money or not, as one example). Graphs are a great way to visually communicate something. Sometimes you don't even need to involve numbers with a graph. Graphs have many other applications.
There are other examples of real world applications of equations, so feel free to search those out.
Answer by ikleyn(52795)  (Show Source):
Answer by josgarithmetic(39618) (Show Source):
You can put this solution on YOUR website! What is y ?
y is a variable.
y is a number which is either known, given, or unknown.
Having an example situation such as y=mx+b, y is NOT to be solved for. An expression is being equated to y.
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