When it's all sides are mutually perpendicular to each other.
The answer is 38, because if you take away the 15 he bought afterwards (34-15) you get 19, and then since he sold half his collection you would double that (19×2) and that's 38.
Both are correct, the earth is about 93 million miles away and Venus is about 67 million miles away from the sun.
Answer:

It has one solution
Step-by-step explanation:
![14x + 12] = 0\\\\14x+12=0\\\mathrm{Subtract\:}12\mathrm{\:from\:both\:sides}\\14x+12-12=0-12\\\\Simplify\\14x=-12\\\\\mathrm{Divide\:both\:sides\:by\:}14\\\frac{14x}{14}=\frac{-12}{14}\\\\Simplify\\x=-\frac{6}{7}](https://tex.z-dn.net/?f=14x%20%2B%2012%5D%20%3D%200%5C%5C%5C%5C14x%2B12%3D0%5C%5C%5Cmathrm%7BSubtract%5C%3A%7D12%5Cmathrm%7B%5C%3Afrom%5C%3Aboth%5C%3Asides%7D%5C%5C14x%2B12-12%3D0-12%5C%5C%5C%5CSimplify%5C%5C14x%3D-12%5C%5C%5C%5C%5Cmathrm%7BDivide%5C%3Aboth%5C%3Asides%5C%3Aby%5C%3A%7D14%5C%5C%5Cfrac%7B14x%7D%7B14%7D%3D%5Cfrac%7B-12%7D%7B14%7D%5C%5C%5C%5CSimplify%5C%5Cx%3D-%5Cfrac%7B6%7D%7B7%7D)
Think of this situation as a system of equations.
let y be the price of hotdogs
let x be the price of hamburgers
5y + 2x = 8
2y + 5x = 9.50
now use your solution method of choice
substitution, elimination, matrices, etc