A1. 12 i.e option D
A2. 3n-7 i.e option A
A3. -6n+20 i.e option D
A4. -70 i.e option C
Step-by-step explanation:
aₙ = a₁ + (n - 1) × d
aₙ = the nᵗʰ term in the sequence
a₁ = the first term in the sequence
d = the common difference between terms
Using the above formula to solve the first part, we have :
For the second part, we have :
For the third part, we have :
For the fourth part, we have :
on the matrix gives![\left[\begin{array}{cc|c}5&5&5\\1&-\dfrac23&5\end{array}\right]\to\left[\begin{array}{cc|c}1&-\dfrac23&5\\5&5&5\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7Cc%7D5%265%265%5C%5C1%26-%5Cdfrac23%265%5Cend%7Barray%7D%5Cright%5D%5Cto%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7Cc%7D1%26-%5Cdfrac23%265%5C%5C5%265%265%5Cend%7Barray%7D%5Cright%5D)