Math, asked by mairawajahat, 9 months ago

In an arithmetic progression the ninth term is 18 and the sum of the first nine terms is 72. Find the common difference and the first term.

Answers

Answered by yajat1810

8

a+8d = 18. (1)

9/2(2a+8d) = 72

a+4d = 8. (2)

(1)-(2)

4d = 10

d = 5/2

a = -2

Previous Question

Next Question

Similar questions

Physics, 4 months ago

where can you see other than the forest...

Math, 4 months ago

bechandripal konse abhiyan dal main shamil hui...

English, 4 months ago

tarun is playing cricket which tense...

Science, 9 months ago

Q1.Multiple choice question i).The process of loosening and turning the soil is called (a) Broadcasting (b) Irrigation (c) Ploughing (d) Levelling ii)The organic substance obtained from dead plants and animal wastes is (a) Manure (b) Fertilizer (c) Irrigation (d) Agriculture iii).In which of the following methods of irrigation rotating nozzles are used? (a) Moat (b) Drip system (c) Chain...

History, 9 months ago

Louis XVI entered into secret negotiation with............................ No spam plz dear...

English, 1 year ago

Expand the theme 1) 'A will ,will find a way'.

Biology, 1 year ago

On a backpacking trip, Kenny hikes all day at a steady pace, covering 30 kilometers and burning 4000 Calories. At the school track, Janelle runs the 100-meter sprint in 13.5 seconds, burning 10 Calories. Afterward, Janelle’s leg muscles are aching and she is breathing hard, while Kenny maintains normal breathing all day, even though he burns 400 times more calories than Janelle. Which two...

Math, 1 year ago

Question 25 (or ↑) and 26 (or ↓). The questions are marked by pencil.