The way that I memorised how to do sin, cos, and tan is by the following: SOH, CAH, TOA
SOH = Sin is OPPOSITE / HYPOTENUSE
CAH = Cos is ADJACENT / HYPOTENUSE
TOA = Tan is OPPOSITE / ADJACENT
For example if we were to solve question 5
Sin T = 6 root 2 / 19
Cos T = 17 / 19
Tan T = 6 root 2 / 17
Repeat the steps for question 6
For the rest of the questions (7,8,9) you have to take the information given and figure out if you should us Sin, cos, or Tan. then plug the numbers in the calculator and while doing sin ^ -1, cos ^ -1, tan ^ -1
for example on question 7, to find the angle x they have given you the hypotenuse and the adjacent side so
cos x = 9 / 18
to find x plug: cos^-1 (9/18) in the calculator
Answer:

<h3>
♁ Question : Solve for x</h3>
<h3>♁ Step - by - step explanation</h3>
Move 12x to L.H.S ( Left Hand Side ) and change it's sign
➛
Move 7 to R.H.S ( Right Hand Side) and change it's sign
➛
Subtract 12x from 15x
Remember that only coefficients of like terms can be added or subtracted.
➛
Add the numbers : 2 and 7
➛
Divide both sides by 3
➛ 
➛ 
The value of x is 
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☄ Now, let's check whether the value of x is 3 or not!
<h3>
☥ Verification :</h3>




L.H.S = R.H.S ( Hence , the value of x is 3 ).
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<h3>✒ Rules for solving an equation :</h3>
- If an equation contains fractions ,multiply each term by the L.C.M of denominators.
- Remove the brackets , if any.
- Collect the terms with the variable to the left hand side and constant terms to the right hand side by changing their sign ' + ' into ' - ' and ' - ' into ' + ' .
- Simplify and get the single term on each side.
- Divide each side by the coefficient of variable and then get the value of variable.
Hope I helped!
Have a wonderful time ! ツ
~TheAnimeGirl
Answer:The expression can be simplified in following steps;
Step-by-step explanation:
(16+a)+15=0
16+15+a=0
31+a=0
a=-31
<span>Well, they couldnt have studied negative time.. So Id say the domain is \(x \ge 0\) where \(x\) is the time they studied.</span>