We're gonna solve x squared plus 13x
plus 36 equals zero using
the quadratic formula.
So our a's, b's, and c's,
a is gonna be the coefficient
for the x squared,
b is the coefficient for the x,
and c is our number at the
end without a variable.
So subbing each of those into our formula
we'll get x equals negative 13
plus or minus the square
root of 13 squared
minus four times one times 36,
all over two times one.
Simplifying that will give us negative 13
plus or minus the square root of 169
minus 144 over two.
Simplifying it even further
we get negative 13 plus or minus
the square root of 25 over two.
Taking it one step further
that ends up being negative 13
plus or minus five over two.
So now we're gonna have
two possible answers for x.
We'll have x equals negative
13 plus five over two
or x equals negative
13 minus five over two.
So negative 13 plus
five is negative eight,
divided by two gives us negative four.
Negative 13 minus five
gives us negative 18,
divided by two gives us our
other answer, negative nine.
