# Thread: [SOLVED] formula for slope?

1. ## [SOLVED] formula for slope?

Hi for a slope equation what is the difference between y=mx+b+c and y=mx+b? what does the constant c stand for?

And also, if the slope passes through the origin what characteristics does it have? and what is the equation (or formula) for it?

2. In the line equation $y = mx + b$, m is the slope, and b is the y-intercept. If the equation were written $y = mx + b + c$, then the y-intercept would be b + c, but this equation is not simplified. If the line passes through the origin, then its y-intercept is 0, and its equation is $y = mx$.

3. Perhaps the c came from the point-slope formula, although I've never seen it written like that.

(y-y_0)=m(x-x_0)

y=mx-(mx_0)+y_0

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If y=mx+b is your line equation, m is the slope and b is the y-intercept. If it passes through the origin, what's the y-intercept? Zero. So the line is simply y=mx.

4. The equation of a line whose slope goes through the origin (and is linear) and is in the form y=mx+b would be y=mx because the y-intercept is zero.

5. Thanks to icemanfan, Jameson and dolphinlover!!