Can Someone tell me how we use the formula y=mx+b

Question

campbell_st · Answer

its the point slope form of a straight line on the number plane

m = slope and b = y intercept... ( where the line cuts the y axis)

e.g. y = 3x + 5    slope 3 and y intercept y = 5

       y = 11 - 2x   slope -2 and y intercept y =11

waheguru · Answer

What is rise/run then?

anonymous · Answer

you use it for linear equations
m is the slope and b is the y intercept
you use the equation to find out x and y

waheguru · Answer

when do we use y=mx+b compared to rise/run

anonymous · Answer

rise/run = whe your plooting points in a graph

campbell_st · Answer

rise over run is used to find m only

waheguru · Answer

then when we are asked to find the slope what do we use ?

anonymous · Answer

so say if its 2/3... ur rise 2 and go right 3.... its used to fing slope as cambell said

waheguru · Answer

what is the prupose of y=mx+b then ?

campbell_st · Answer

ok... can you draw the line y = 2x - 3

waheguru · Answer

no

campbell_st · Answer

ok... I think you need to learn a little substitution algebra

anonymous · Answer

Find the equation of the straight line that has slope m = 4
    and passes through the point (–1, –6).

    Okay, they've given me the value of the slope; in this case, m = 4. Also, in giving me a point on the line, they have given me an x-value and a y-value for this line: x = –1 and y = –6.

    In the slope-intercept form of a straight line, I have y, m, x, and b. So the only thing I don't have so far is a value for is b (which gives me the y-intercept). Then all I need to do is plug in what they gave me for the slope and the x and y from this particular point, and then solve for b:

        y = mx + b
        (–6) = (4)(–1) + b
        –6 = –4 + b
        –2 = b

    Then the line equation must be "y = 4x – 2".

waheguru · Answer

Oh, so y=mx+b is an equation to bascially find everything about a line where as riseérun is the slope which can be used in the equation to find other values right?

anonymous · Answer

and if you were to graph this, you would start at -2 and you would go up 4 over up 4 and over and so on

campbell_st · Answer

correct

waheguru · Answer

So when A question shows me a line and I need to find the slpoe I use rise/run and when i need to make an equation i use y=mx+B

campbell_st · Answer

thats it...

waheguru · Answer

Thanks!