Answer:
A
Step-by-step explanation:
6x- 3x + 6=18
6(4)- 3(4) + 6=18
24-12 + 6=18
12 +6=18
18=18
Answer:
1) James brother is 10-x years old
2) James was 3 years ago x-3 years old
3) James brother was 3 years ago 7-x years old
4) 3(x-3)=7-x
5) James is 4 years old, his brother is 6 years old
Step-by-step explanation:
3) 10 - x - 3 = 7 - x
5) 3* James age 3 years ago = James brothers age 3 years ago
<=> 3*(x-3) = 7-x
<=> 3x - 9 = 7 - x
<=> 4x = 16
<=> x = 4
Answer:
Part 4) 
Part 10) The angle of elevation is 
Part 11) The angle of depression is 
Part 12)
or 
Part 13)
or 
Step-by-step explanation:
Part 4) we have that

The angle theta lies in Quadrant II
so
The sine of angle theta is positive
Remember that

substitute the given value




Part 10)
Let
----> angle of elevation
we know that
----> opposite side angle theta divided by adjacent side angle theta

Part 11)
Let
----> angle of depression
we know that
----> opposite side angle theta divided by hypotenuse


Part 12) What is the exact value of arcsin(0.5)?
Remember that

therefore
-----> has two solutions
----> I Quadrant
or
----> II Quadrant
Part 13) What is the exact value of 
The sine is negative
so
The angle lies in Quadrant III or Quadrant IV
Remember that

therefore
----> has two solutions
----> IV Quadrant
or
----> III Quadrant