Find the measure of the line segment de.

a) 15

b) 13

c) 21
d) 18

A) 15

Step-by-step explanation:

triangle DGF ~ triangle LEF

GF/EF=DF/LF

7/6=(4x-1+6)/(11+7)

7/6=(4x+5)/18

4x=16

x=4

DE=4*4 - 1=15

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.