Final Answer: 
Steps/Equations:
Question: 
Step 1: Move the negative sign to the left side.

Step 2: Multiply both sides by
.

Step 3: Simplify
to
.

Step 4: Multiply both sides by
.

~I hope I helped :)~
Answer: the box contained 9 square chocolates and 15 round chocolates.
Step-by-step explanation:
Let x represent the number of square chocolates contained in the box.
Let y represent the number of round chocolates contained in the box.
The box of chocolates contains square chocolates, which weigh 10g each and round chocolates which weigh 8g each. The combined weight of all the chocolates is 210g. It means that
10x + 8y = 210- - - - - - - - - - -1
The number of round chocolates is 3 less than twice the number of square chocolates. It means that
y = 2x - 3
Substituting y = 2x - 3 into equation 1, it becomes
10x + 8(2x - 3) = 210
10x + 16x - 24 = 210
26x = 210 + 24
26x = 234
x = 234/26
x = 9
y = 2x - 3 = 2 × 9 - 3
y = 18 - 3
y = 15
In order to solve this problem, you must draw a right triangle first to help you visualize the path of the jogger.
You are given 0.5 miles north (which will be the height of the right triangle), and 1.3 miles (which will be the hypotenuse of the triangle).
Using Pythagorean Theorem: a²+b²=c², we have:
0.5² + b² = 1.3²
b = 1.3²-0.5²
b = 1.2 miles