Give the slope and y-intercept for the equation: y=3x-2
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ChandrikaP
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Y=3x-2
y intercept means where x=0
put x=0 in the equation
y=3(0)-2
Y=-2
if we start with this general form:
Ax + By + C=0
Then the slope of the line is:
slope = m = -A/B
And the y-intercept is:
y-intercept = b = -C/B
so in this equation y=3x-2
c=-2
b=1
slope=2/1
slope=2
Hope that will help you....
mmm4444bot
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You're correct, up to this point.
(I changed symbols Y above to y; it's best to use just one symbol.)
Remember, A=-3, B=1, C=2
-3x + y + 2 = 0 :cool:
mmm4444bot
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Hi. It's easy to answer, if you've learned this special form:
Slope-Intercept Form
Have you seen it? Google "slope intercept form", or look it up in your textbook's index. You'll learn that the equation y=3x-2 is written in Slope-Intercept Form because the two numbers shown are the slope and the y-intercept.
If you're not sure what "slope" or "y-intercept" mean, then you ought to learn those names first.
Let us know, if you have any questions about what you read in your textbook or see in online lessons. :cool:
mmm4444bot
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If you already know the concepts of "slope" and "y-intercept", check out this short video:
http://www.virtualnerd.com/algebra-...form-examples/slope-intercept-form-definition
http://www.virtualnerd.com/algebra-...form-examples/slope-intercept-form-definition
Im confused, i thought in slope intercept form the 3x would be the slope. But you're saying its 2?Y=3x-2
y intercept means where x=0
put x=0 in the equation
y=3(0)-2
Y=-2
if we start with this general form:
Ax + By + C=0
Then the slope of the line is:
slope = m = -A/B
And the y-intercept is:
y-intercept = b = -C/B
so in this equation y=3x-2
c=-2
b=1
slope=2/1
slope=2
Hope that will help you....
Harry_the_cat
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y=mx +b is in slope intercept form where slope = m and y-int=b.
You are correct (almost). Slope =3 in your question (not 3x just 3).
ChandrikaP
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Hi Bronn,
first of all sorry i solved it wrong as i just put those values in y intercept equation,
Ax+By+C=0
Y=3X-2
3X-Y-2=0
m(slope)=-A/B
A=3,B=-1
here A=-(-3)/1
slope=3
Harry_the_cat
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see comment in red
I may aswell ask here. Ive just been learning this stuff. Ive been confused what the C represents. I get that M is slope, the ab and xy are coordinates right? but what does the C represent?
Harry_the_cat
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Hi Bronn,
There are basically two forms of the equation of a straight line.
1. Gradient intercept form: \(\displaystyle y = mx+c \). This form always starts with \(\displaystyle y=\). The gradient is m (the coefficient of x) and the y-intercept is c (constant term).
In this form it is easy to just pick out the gradient and y-intercept. Hence the name.
2. Standard form: \(\displaystyle Ax + By +C = 0\)
This form can be rearranged into gradient-intercept form in the following way:
\(\displaystyle Ax + By + C =0\)
\(\displaystyle By= -Ax - C\)
\(\displaystyle y=\frac{-A}{B}x - \frac{C}{B}\)
So the gradient (the coefficient of x) = \(\displaystyle \frac{-A}{B}\) and the y-intercept is \(\displaystyle \frac{-C}{B}\).
Note that the c's mean different things. That's why one is usually lower case and one upper case.
(x, y) represents points on the line and are the variables. A and B and C OR m and c are constants for a particular line.
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so the A and B are constants in standard form, not the same as the (a,b) in point slope form? i.e. (y-b) = m(x-a)
this could get confusing for me..
edit: after clicking the point slope link above, i see maybe using (a,b) in point slope form is a kahn academy thing
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