CAT Exam Model Paper 2 with solutions for free online practice

(c) Given, x( x + y + z) = 9 ...(i)
y( x + y + z) = 16 ...(ii)
z( x + y + z) = 144 (iii)
On adding Eqs. (i), (ii) and (iii), we get
x( x + y + z) + y( x + y + z)+ z( x + y+ z)= 9 + 16 + 144
⇒ ( x + y + z)( x + y + z) = 169
⇒ ( x + y + z)${}^2$ = 169
⇒ x + y + z = 13 ...(iv)
On putting the values of ( x + y + z) from Eq. (iv) in Eq. (i), we get
x( x + y + z) = 9
⇒ x(13) = 9 ⇒ x = $\frac{9}{13}$