Question

Four consecutive terms are in the a. p whose sum is 42 and product of1 st and 4 term is 90 find all the terms.

Answer 1

Answer:

9,10,11,12

Step-by-step explanation:

let the 4 consecutive terms be a,a+d,a+2d,a+3d

GIVEN,

a+(a+d)+(a+2d)+(a+3d)=42

4a+6d=42

2a+3d=21 ........>  1

GIVEN,

a(a+3d)=90

a(a+21-2a)=90                 [2a+3d=21]

a²-21a+90=0

a=12   or   a=9

from   1

if a=12;d=-1    

if a=9;d=1

terms are

a=12                              a=9

a+d=11                           a+d=10

a+2d=10                        a+2d=11

a+3d=9                          a+3d=12