Andrea's record label released her new album. Andrea wants to know when she has sales of at least $20,000 per week. She uses the related equation below to determine when sales will be at least this amount, where t represents time in weeks.

please finish the other half

Andreas record label released her new album Andrea wants to know when she has sales of at least 20000 per week She uses the related equation below to determine class=

Respuesta :

Answer:

  • 10 ≤ t ≤ 20 or t ∈ [10; 20]

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The other half is:

  • t - 15 ≥ - 5
  • t  ≥ - 5 + 15
  • t  ≥ 10

The answer, considering both halves, is:

  • 10 ≤ t ≤ 20

or

  • t ∈ [10; 20]

Answer:

[tex]10 \leq t \leq 20[/tex]

Step-by-step explanation:

Given absolute value inequality:

[tex]1000(-2|t-15|+30) \geq 20000[/tex]

Isolate the absolute value on one side of the equation:

[tex]\implies \dfrac{1000-2|t-15|+30)}{1000} \geq \dfrac{20000}{1000}[/tex]

[tex]\implies -2|t-15|+30 \geq 20[/tex]

[tex]\implies -2|t-15|+30-30 \geq 20-30[/tex]

[tex]\implies -2|t-15|\geq -10[/tex]

[tex]\implies \dfrac{-2|t-15|}{-2}\geq \dfrac{-10}{-2}[/tex]

[tex]\implies |t-15|\leq 5[/tex]

[tex]\textsf{Apply absolute rule:\quad {If} $|u| \leq a, \;a > 0$ \;then\; $-a \leq u \leq a$}[/tex]

[tex]\implies -5 \leq t-15\leq 5[/tex]

Solve both equations:

[tex]\begin{aligned}\underline{\sf Equation\;1} && \underline{\sf Equation\;2}\\t-15 &\geq -5 \quad & t-15& \leq 5\\t-15+15& \geq-5+15 &\qquad t-15+15& \leq 5+15\\t&\geq10 & t &\leq20\end{aligned}[/tex]

Merge the overlapping intervals:

[tex]10 \leq t \leq 20[/tex]