Answer:

Step-by-step explanation:
Given

Required
The phase
We have:

Rewrite as:

A cosine function is represented as:

Where:
Phase
By comparison:

Hence, the phase is: 
Answer: Y= -x/5 + 32/5
Step-by-step explanation:
x + 7 = 2(3x - 4) Remove the brackets
x + 7 = 2*3x - 4*2
x + 7 = 6x - 8 Subtract 7 from both sides.
x + 7 - 7 = 6x - 8 - 7
x = 6x - 15 Subtract 6x from both sides
x - 6x = - 15
-5x = - 15 Divide by -5
-5x/-5 = -15/-5
x = 3