There are two parts in the given collection. One contains quarters and other contains dimes.
Let's compare the whole coin collection to the quarters.
One way to represent the ratio is 15 : 7.
The other way is 
Equations with absolute value:

Where k is a positive number; if k is a negative number, the equation is impossible (absolute value is always positive).
How to solve:


Then:
1. |x+7|=12
x+7=12 V -x-7=12
x=5 V -x=19
x=5 V x=-19
{-19, 5}
2. |2x+4|=8
2x+4=8 V -2x-4=8
2x=4 V -2x=12
x=2 V x=-6
3. 3|3k|=27
3×3k=27 V 3×(-3k)=27
9k=27 V -9k=27
k=3 V k=-3
{-3, 3}
4. 5|b+8|=30
5×(b+8)=30 V 5×(-b-8)=30
5b+40=30 V -5b-40=30
5b=-10 V -5b=70
b=-2 V b=-14
{-14, -2}
5. |m+9|=5
m+9=5 V -m-9=5
m+9=5 V m+9=-5
Answer:
Skiing costs $30 per hour and Boating costs $51 per hour.
Step-by-step explanation:
Let cost per hour of skiing be x and cost per hour of boating be y. Let's dissect the problem into 2 simultaneous equations.
<em><u>"John paid $222 for four hours of skiing and two hours boating":</u></em>

<em><u>"He paid $213 for two hours skiing and three hours boating":</u></em>

<em>Now, if we solve for x in the 2nd equation and plug it in the 1st equation, we will have the value for y</em>. Work shown below.

Hence, y = 51
<em>Now, substituting this y value into the 1st equation and solving for x will give us the value of x.</em>

Hence, skiing costs $30 per hour and boating costs $51 per hour.
An isosceles triangle has two equal sides and one unique side
Hope this helps!
- Z
Answer:
The repair person did 5 hours of work.
Step-by-step explanation:
155 = 25x + 30
125 = 25x
5 = x