For this case we must propose an algebraic expression associated with:
"four times a difference of a number and seven is 12"
So we have to:
Four times a difference of a number and seven is represented as: 
So we have the expression is:

We apply distributive property to the terms within parentheses:

We add 28 to both sides:

We divide between 4 on both sides:

Answer:

Answer: Unit rate = 4/35 of a gallon per hour
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Work Shown:
3 & 1/2 = 3 + 1/2
3 & 1/2 = 6/2 + 1/2
3 & 1/2 = (6+1)/2
3 & 1/2 = 7/2
The faucet drips 2/5 of a gallon in 7/2 hours
2/5 gallon : 7/2 hours
2*(2/5 gallon) : 2*(7/2 hours) ..... multiply both sides by 2
4/5 gallon : 7 hours
(1/7)*(4/5 gallon) : (1/7)*(7 hours) ... multiply both sides by 1/7
4/35 gallon : 1 hour
The unit rate is 4/35 of a gallon per hour.
"Per hour" means "every 1 hour".
This is the solution using substitution. Hope this helps!
You can use the identity

The sign is negative because the angle is in the 3rd quadrant.
This corresponds to ...
a. -(4√17)/17
Answer:
-2
Step-by-step explanation:
They are asking for the slope. y2-y1/x2-x1
Make a table of results for the equation
x y
5 -2(5)+1=-10+1=-9 Y1
6 -2(6)+1=-12+1=-11 Y2
-11--9=-11+9=-2
6-5=1
Average rate pf change os -2/1=-2