39=9x+7-3x+20
Subtract 27 from each side
12=6x
2=x
Now plug in 2 for x to find AB and BC
9x+7= AB
9(2)+7=AB
18+7= AB
25= AB
-3x+20= BC
-3(2)+20= BC
-6+20= BC
14= BC
Answer: D is correctly written in scientific notation.
Step-by-step explanation:
The base has to be between 1 and 10.
A has a base of 16.4 which is greater than 9.
B is not even in scientific because the base it being raise to an exponent
C has 0.71 as base which is less that.
Use: (a + b)(c + d) = ac + ad + bc + bd

Answer:
d. x² + 6x +8
Answer:
C. the average total cost for the first month of a gym membership
Step-by-step explanation:
x=1 is for month 1,
the value of y includes 1-month fee and one off payment, so this is the average total for the first month of membership