Answer:
Stephanie saved
Step-by-step explanation:
x+4x=15600
5x=15600
divide by 5 on both sides
you get 3120
since stephanie got 4 times more, you multiply 3120*4 and get 12480
therefore, Alejandro saved 3120
: )
Answer:
it is 7x-4
Step-by-step explanation:
Answer:
(a)Therefore the value of x=
(b) Therefore the value of x 
Step-by-step explanation:
Horizontal tangent line: The first order derivative of a function gives the slope of the tangent of the function. The slope of horizontal line is zero.If the slope of tangent line is zero then the tangent line is called horizontal tangent line.
(a)
Given function is,

Differential with respect to x

For horizontal tangent line, f'(x)=0
3+ 3 cos x= 0
⇒3 cos x=-3
⇒cos x=-1
⇒x = 180° 
Therefore the value of x=
(b)
Given that, the slope is 3.
Then,f'(x)=3
3+ 3 cos x= 3
⇒3 cos x= 3-3
⇒cos x=0
⇒x = 90° 
Therefore the value of x 
Triangle 3 because its length is longer than the others.
90°-77°=13°.
the answer is 13°