Answer:
7i..........................
Answer:
Marco's age is 7 years old
Step-by-step explanation:
Let
x ----> Marco's age
y ----> Paolo's age
we know that
---->
----> equation A
----> equation B
substitute equation A in equation B
![x(x+8)=105](https://tex.z-dn.net/?f=x%28x%2B8%29%3D105)
![x^2+8x-105=0](https://tex.z-dn.net/?f=x%5E2%2B8x-105%3D0)
Solve the quadratic equation
The formula to solve a quadratic equation of the form
is equal to
![x=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-b%28%2B%2F-%29%5Csqrt%7Bb%5E%7B2%7D-4ac%7D%7D%20%7B2a%7D)
in this problem we have
![x^2+8x-105=0](https://tex.z-dn.net/?f=x%5E2%2B8x-105%3D0)
so
![a=1\\b=8\\c=-105](https://tex.z-dn.net/?f=a%3D1%5C%5Cb%3D8%5C%5Cc%3D-105)
substitute in the formula
![x=\frac{-8(+/-)\sqrt{8^{2}-4(1)(-105)}} {2(1)}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-8%28%2B%2F-%29%5Csqrt%7B8%5E%7B2%7D-4%281%29%28-105%29%7D%7D%20%7B2%281%29%7D)
![x=\frac{-8(+/-)\sqrt{484}} {2}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-8%28%2B%2F-%29%5Csqrt%7B484%7D%7D%20%7B2%7D)
![x=\frac{-8(+/-)22} {2}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-8%28%2B%2F-%2922%7D%20%7B2%7D)
![x=\frac{-8(+)22} {2}=7](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-8%28%2B%2922%7D%20%7B2%7D%3D7)
![x=\frac{-8(-)22} {2}=-15](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-8%28-%2922%7D%20%7B2%7D%3D-15)
Remember that the solution cannot be a negative number
so
The solution is x=7
therefore
Marco's age is 7 years old
The two expressions are not equal
A=pe^rt ,,,
6500=5000e^(5r),,,
Solve for r,,,
R=(log(6,500÷5,000)÷log(e))÷5,,,
R=0.05247
---------
A=5,000×e^(0.05247×16),,,
A=11,576.28,,,
360 is the answer.
I hope this helps. :)