4. Henry is a carpenter. He received an order to make an attractive and light weight metal frame door. He has two options: one is an iron frame door. The
second is an aluminum frame door.
The volume and density of the iron frame is respectively 1350 ml, and 7.87 g/ml.
The volume and density of the aluminum frame is respectively 2850 ml and 2.7
g/ml.
The customer wants the lightest door frame possible. Which one is the right
option for the door?

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.

the answer is c.

step-by-step explanation:

sina-sinb

cosb+cosa

tana-tanb

cos0+cos x pi/3

20tan

step-by-step explanation:

df =

both have same length