+191 Hi Everyone, could you help me! I m going crazy :(
Find the slope of the following lines :
(a). y = 100 - 15x
(b). A(t) = 150000 - 300t
If someone could take his time to explain me how to solve this ??
I would appreciated so much !
Best,
Thank you
Thalys
+191 Hi, Thanks for you answer,
However I did not find -15 but onlny 15 for the slope of 100-15x
How did you find the b : A(t) = 150000 - 300t ??
Best,
Thalys
+118608 Hi Thalys,
Omi67's answers are excellent.
I will just reiterate.
I might use a different example :/
Both yours are the equation of lines.
Lines are oftenpresented in the form
y=mx+b (This is called gradient and y intercept form of a line)
m and b are just numbers.
for example y=3x-6
In this example m=3 and b=-6 (it is -6 because you added -6 y=3x+-6)
Now if you were going to find the y intercept in this example you could put x=0
and you would get
y=3*0-6
y=-6
See how the tacked on "-6" IS the y intercept. It always works this way.
The tacked on "b" IS the y intercept.
---------------
Now slope is another name for gradient.
\(gradient (slope) =\frac{rise}{run}\)
I was going to do a whole lot more but I might leave it for the moment.
---------------------
The gradient is given by the number in front of the x (this is the co-efficient of x)
In this example the number in front of x is 3 SO the slope(gradient) is 3
I could have written my line as
y= -6+3x
This is back to front. I want the lots of x first so I am going to rearrange it.
y = -6 +3x
the terms are -6 and +3x
I need them the other way around
+3x and -6
SO my equations is better written as
y=+3x-6
y= 3x-6
this is now in gradient and y intercept form y=mx+b
b, the y intercept, is -6
and
m, the gradient (slope) is +3
-----------------------------------------------------------------
In your example a)
y= 100 -15x
it is written back to front
you need to put the lots of x first. Remember that there is an invisable + in front of the 100
y = +100 -15x
y= -15x +100
The y intercept is the number tacked on the end, it is usually given the letter b and it is 100
The gradient is given the letter m and it is -15
-----------------------------------------------------
You should be able to do b yourself now :))
(b). A(t) = 150000 - 300t
