Hello,
3^x+1=15
==>3^x=14
==>x*ln(3)=ln(14)
==>x=ln(14)/ln(3)
==>x=2,40217350273....
Answers:

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Work shown for part 1

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Work shown for part 2

3n-16<8
3n<24
n<8
............
Answer:
The y-axis is the correct answer.
y = -2x - 3
-- The y-intercept is the point where the graph crosses
the y-axis. But x=0 everywhere on the y-axis, so
y = -2(0) - 3
y = - 3 .
-- The x-intercept is the point where the graph crosses
the x-axis. But y=0 everywhere on the x-axis, so
0 = -2x - 3
Add 2x to each side: 2x = -3
Divide each side by 2: x = -3/2 .