Answer:
Step-by-step explanation:
1.

c+9=±8
either c=8-9=-1
c=-8-9=-17
so c=-1,-17
D
2.
8x^2-3=2
8x^2=5


so A
3.

so D
or
7% = 0.07
Price of the book = x
x + 0.07x + 4.5 = 31.25
1.07x + 4.5 = 31.25
1.07x = 26.75
x = 25
Pre Tax Price = $25
Step-by-step explanation:
sec x − cos x
Secant is the inverse of cosine:
(1 / cos x) − cos x
Find the common denominator:
(1 / cos x) − (cos² x / cos x)
Subtract:
(1 − cos² x) / cos x
The answer is true because it is the same