Answer To (b): 10 sandwiches in 20 minutes. But If Your Friend Arrived 10 Minutes Earlier, Then He Can Make 20 Sandwiches In The 20 Minutes That You Are There. If He Started When He Arrived And The Twenty Minutes Started Then, You Can Only Make 5.
Answer:
if 
Step-by-step explanation:
Recall some following basic ideas about absolute value:
or I guess 

or just
but there is a reason why I wrote it the way I did.
You see that the absolute value returned the same value if the value was positive.
You see that the absolute value returned the opposite value if the value was negative.
You can include 0 in either.
Let's look at
alone for a second.
*
if
is positive or zero.
When is
positive or zero? [greater than or equal to 0]

Subtract 3 on both sides

*
if
is negative or zero.
When is
negative or zero? [less or equal to 0]

Subtract 3 on both sides

So looking at the bullet points (the *),
fits into the first inequality.
Therefore,
.
Answer:
She didn't put the sign's in the proper place, it should be ( x + 3 ) ( x - 7 )
Step-by-step explanation:
( x - 3 ) ( x + 7 ) = x² + 7x - 3x - 21 = x² + 4x - 21
( x + 3 ) ( x - 7 ) = x² - 7x + 3x - 21 = x² - 4x - 21