Answer:
See Explanation
Step-by-step explanation:
<em>Question like this are better answered if there are list of options; However, I'll simplify as far as the expression can be simplified</em>
Given

Required
Simplify

Represent
with a
Represent
with b
The expression becomes

Factorize



Recall that

The expression
becomes

..............................................................................................................................
In trigonometry

Subtract
from both sides


..............................................................................................................................
Substitute 1 for
in 

Open Bracket
------------------This is an equivalence

Solving further;
................................................................................................................................
In trigonometry


Substitute the expressions for secx and tanx
................................................................................................................................
becomes

Open bracket


Add Fraction
------------------------ This is another equivalence
................................................................................................................................
In trigonometry

Make
the subject of formula

................................................................................................................................
Substitute the expressions for
for 

Open bracket

---------------------- This is another equivalence
0.8(5x + 15) = 2.6 - x + 3 Use the Distributive Property
4x + 12 = 2.6 - x + 3 Combine like terms (2.6 and 3)
4x + 12 = 5.6 - x Add x to both sides
5x + 12 = 5.6 Subtract 12 from both sides
5x = -6.4 Divide both sides by 5
x = -1.28
6 hardcover books for 26 dollars
let the number of adult tickets be x and the number of children tickets be y
3x + y = 164...equ(1)
2x + 3y = 174....equ(2)
multiplying equation 1 by 3
9x + 3y = 492
subtracting equation 2 from 1
7x = 318
x = 45.43 dollars
substituting the value of x into the equation
3(45.428) + y = 164
y = 164 - 3(45.428)
∴y = 27.71 dollars
Answer:
5
Step-by-step explanation: