28 - 5b
5b = 15
28-15 = 13
i hope this is what you are looking for : )
x= -3 and
to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into
where a is the cube root of .
here this is 27 and the cube root of 27 is 3. so we write using the form:
set each factor to 0 and solve for x.
the quadratic expression does not factor and must be solved using the quadratic formula.
where a = 1, b=3, and c=9
this cubic has two complex roots.