Answer: 59 + b
Step-by-step explanation: I hope this is what you mean by writing an expression
Answer:63
Step-by-step explanation:
Answer:
45
Step-by-step explanation:
Let the first term be a and the common difference be d.
So -18=4a+6d and -9=6a+15d. Solving this we get a=-9 and d=3.
So the sum of first 10 terms is 5*(2*(-9)+9*(3))=45