here we have a quadratic equation in
standard form it asks us to use the
quadratic formula so let's first
identify a B and C the coefficient on x
squared is a is 1 B is negative 5 and
notice there's no constant term so C
then we could think of as zero okay so
here's the quadratic formula now let's
go ahead and substitute in the
appropriate value so negative B negative
negative 5 plus or minus the square root
of B squared so negative 5 squared minus
4 times a times C notice there C is 0
all divided by two times a okay and then
simplifying we're left with 5 plus or
minus the square root negative 5 squared
is 25 and then minus 4 times 1 times 0
anything times 0 is 0 all divided by 2
okay so 5 plus or minus 5 all divided by
2 so this tells me I get two solutions
the first solution here is 5 minus 5
divided by 2 and the second solution is
5 plus 5 divided by 2 okay 5 minus 5 is
0 0 divided by a number is just 0 so one
solution is 0 and the other one here I
have 10 divided by 2 or 5 so here's my
two solutions 0 and 5 certainly you can
go back to the original plug in and see
if they work and right away you can see
0 works right 0 squared minus 5 times 0
is certainly 0 and you can also
substitute in 5 and see if that works as
well
