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all right what I'd like to do is show
you guys how to find X and y-intercept
from an equation 2x minus 5y equals 1
now we give it a graph it's very easy to
remember with y and x intercept R
because we know that the point where it
crosses the y axis that's your
y-intercept ok and we know that it's
going to be at some point 0 comma Y and
our x intercept 3 crosses the x axis and
that is at some point X comma 0 that's
what we call the x-intercept
so it's very easy to remember on a graph
all of its where it crosses each axis
however we come into the problem when we
start doing the equation because here I
don't know what this graph looks like
now we are going to learn later how to
graph this equation but there's a very
simple way we can also do this
algebraically that will help us find the
x and y intercepts and then also learn
how to graph it later
so the one key important thing I want to
that I want to take from this route is
we notice that when the y intercept at
the y intercept X is 0 and at the x
intercept our Y value is 0 because
remember a coordinate point is X comma Y
so here x equals 0 and x intercept is y
0 so I'm going to go ahead and erase
this and then write those two properties
so at the y intercept X is equal 0 and
the x intercept Y is equal
okay so what does it mean 1 1 values
equal to 0 well what we can do is we can
treat this as a function if we say 0 X
is now equal 0 I'm going to now evaluate
this for when X is equal to 0 so I'm
going to plug in 2 times 0 minus 5 times
y equal 1 and then over here I'm going
to say 2x minus 5 times 0 equals 1 so
now looking at these two equations now
what I'm going to do is for this one I'm
going to solve for my variable Y and for
this problem you solved for my variable
X so I know that anything multiplied by
0 is 0 so I'm just going to kind of
cancel them out so never want month with
no minute 5 y equals 1 and over here we
have 2 x equals 1 so now we're just
going to go ahead and simply go ahead
and use our division division property
of equality and since my negative 5 is
multiplied by my Y I'm going to divide
by negative 5 on both sides and here I'm
going to divide by 2 the whole surface
therefore x equals 1/2 and here y equals
negative 1/5
so when go ahead and graph you my two
points if I know that here's my
y-intercept I know that X is zero and my
y value is negative one-fifth
my point is 0 and a 1 bit and my point
here is going to be 1/2 0 so I can go
ahead and plot these two points and they
would be the two intercepts on my
equation alright so that's how you find
the X and y intercept from an equation
