Question

Find the first term if second , third and fourth terms are 21,80,120

Answer 1

Given

a₂ = 21

=> a + d = 21 --- (1)

a₃ = 80

=> a + 2d = 80---(2)

Solving (1) and (2), we get,

$2a+2d=42\\ \underline{a+2d=80}\\\underline{\underline{a = -38}}\\\\\implies \boxed{\boxed{\bold{ The \ first \ term \ is \ -38}}}$

                                                           

Answer 2

Answer:

a₂ = 21

=> a + d = 21 --- (1)

a₃ = 80

=> a + 2d = 80---(2)

Solving (1) and (2), we get,

Step-by-step explanation: