Step-by-step explanation:
=== [ -3(x-10)/4] + 2 = 11
==> [( -3x + 30 + 8)/4 = 11
==> -3x = 44 - 38
==> -3x = 6
==> -x = 6/3
==> x = -2
Answer:
6 and 21 meters long
Step-by-step explanation:
You make an equation from what you got (there are 2 widths and 2 lengths)
2(4w-3)+2w=54---->10w-6=54---> 10w=60 ----> w=6 ---> plug in the rest and you get 21 as the length.
or... make W+L=28 and guess and check!!! takes longer but works!
A. Or B. Sorry if I’m wrong tho :-(
Answer:
cos 2Ф = - 161/289 , tan 2Ф = - 240/161
Step-by-step explanation:
* Lets explain how to solve the problem
∵ cos Ф = - 8/17
∵ Ф lies in the 3rd quadrant
- In the 3rd quadrant sin and cos are negative values, but tan is
a positive value
∵ sin²Ф + cos²Ф = 1
∴ sin²Ф + (-8/17)² = 1
∴ sin²Ф + 64/289 = 1
- Subtract 64/289 from both sides
∴ sin²Ф = 225/289 ⇒ take √ for both sides
∴ sin Ф = ± 15/17
∵ Ф lies in the 3rd quadrant
∴ sin Ф = -15/17
∵ cos 2Ф = 2cos²Ф - 1 ⇒ the rule of the double angle
∵ cos Ф = - 8/17
∴ cos 2Ф = 2(-8/17)² - 1 = (128/289) - 1 = - 161/289
* cos 2Ф = - 161/289
∵ tan 2Ф = sin 2Ф/cos 2Ф
∵ sin 2Ф = 2 sin Ф × cos Ф
∵ sin Ф = - 15/17 and cos Ф = - 8/17
∴ sin 2Ф = 2 × (-15/17) × (-8/17) = 240/289
∵ cos 2Ф = - 161/289
∴ tan 2Ф = (240/289)/(-161/289) = - 240/161
* tan 2Ф = - 240/161
