Create a model to compare these two texting plans:
a. plan a costs $15 a month, including 200 free texts. after 200, they cost $0.15 each.
b. plan b costs $20 a month, including 250 free texts. after 250, they cost $0.10 each.

Step-by-step explanation:

Let x = number of texts

For plan A

Plan A costs $15 a month, including 200 free texts. After 200, they cost $0.15 each. It means that plan A has a base cost of $15 monthly and charge $0.15 for (total texts - 200 free texts). The model becomes

Cost of plan A = 15 + 0.15(x -200)

For plan B

Plan B costs $20 a month, including 250 free texts. After 250, they cost $0.10 each. It means that plan B has a base cost of $20 monthly and charge $0.10 for (total texts - 250 free texts). The model becomes

Cost of plan B = 20 + 0.10(x -250)

the answer to your question a or b but i am pretty sure it is b. i hope this : )

step-by-step explanation:

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.