CDS Model Paper 1 Mathematics

Given,

5x−7y+10

1

=

3x+2y+1

8

=

11x+4y−10

9

=

(5x+10−7y)+(3x+2y+1)−(11x+4y−10)

(1+8)−9

=

−3x−9y+21

0

⇒ x+3y=7 ...(i)
On taking first two terms,
8(5x−7y+10)=3x+2y+1
37x−58y+79=0 ....(ii)
From equation (i), on putting the value of x in equation (ii), we get
37(7−3y)−58y+79=0
⇒ 259−111y−58y+79=0
⇒ 169y=338
⇒ y=2
From equation (i),
x=7−3(2)=1
∴ x+y=1+2=3