Please help me out! I don't understand this

CD=EF. -(1)

EF=GH. -(2)

Adding (1) and (2)

[LHS(1)+LHS(2) = RHS(1)+RHS(2)]

CD+EF = EF+GH

EF on both sides cancel each other.

CD= GH

Option D is the answer.

Hope this will help :-)

x= -3 and

step-by-step explanation:

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.

x-3=0

x=3

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.