3t – 4(t – 5) + 5 for t=6. 2

18.8

Step-by-step explanation:

3t - 4(t - 5) + 5 (plug in 6.2 as t)

3(6.2) - 4(6.2 - 5) + 5 (distribute 3 to 6.2)(subtract 5 from 6.2)

18.6 - 4(1.2) + 5 (multiply -4 and 1.2)

18.6 - 4.8 + 5 (subtract 4.8 from 18.6)

13.8 + 5 (add 13.8 and 5)

18.8

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.