Answer:
<h2>
![\bold{a_7=33x-15}](https://tex.z-dn.net/?f=%5Cbold%7Ba_7%3D33x-15%7D)
</h2>
Step-by-step explanation:
In arithmetic sequence: a₂ - a₁ = a₃ - a₂ {common difference}
![a_1=5x+9\\a_2=8x+5\\a_3=11x+1\\\\\\d=8x+5-(5x+9)=8x+5-5x-9=3x-4\\\\a_n=a_1+d(n-1)\\\\a_7=5x+9+(3x-4)\cdot6\\\\a_7=5x+9+18x-24\\\\a_7=33x-15](https://tex.z-dn.net/?f=a_1%3D5x%2B9%5C%5Ca_2%3D8x%2B5%5C%5Ca_3%3D11x%2B1%5C%5C%5C%5C%5C%5Cd%3D8x%2B5-%285x%2B9%29%3D8x%2B5-5x-9%3D3x-4%5C%5C%5C%5Ca_n%3Da_1%2Bd%28n-1%29%5C%5C%5C%5Ca_7%3D5x%2B9%2B%283x-4%29%5Ccdot6%5C%5C%5C%5Ca_7%3D5x%2B9%2B18x-24%5C%5C%5C%5Ca_7%3D33x-15)
Answer:
6 or 5
Step-by-step explanation:
I don't understand or see for the matter the question what is it
This is how I would solve it, I would act as if there were 36 people in the class.
36÷6=6×5=30
30÷3=10×2=20
20/36=10/18=5/9
You could also try another number such as 24;
24×(5÷6)=20
20×(2/3)=13.3(3 repeating)
13.333/24=5/9
5/9 people have dogs.
Tell me if this helps.