Answer:
39
Step-by-step explanation:

2x+1=13 x=6 so an ok answer would be: 2x+10=40 x=15
Answer:
z*(z - 3) = 520
Step-by-step explanation:
Use the following representations:
Width: W
Length: L = W + 3, or W = L - 3
Area = L*W = L*(L - 3) = 520
Equation b) is the correct one: z*(z - 3) = 520
Answer:
C
Step-by-step explanation:
The key lies in translating "1/10 percent." If the unknown number is n, then 0.001n = 10. Mult. both sides by 1000: n = 10000 (answer)