Multiply (1) by 5, (2) by 3, and subtract;

..

=

(1)

find x and

y.

(2)

25-9.40-27

X=

13
16 × 12

5 × 13

3y

=

I

4

13

=

192 192

Multiply (1) by ———, (2) by, and subtract;

a

x-2y+ 2 = 0 (3)

Adding (2) and (3) we get, −4x + 7y = 22......... (4),

from (1) 3-7y+42 = 1,
from (3) 4x-8y + 42 = 0 ;

From (1), (26x + 132 − 52) + (36y — 72z + 12) = 39x — 78, whence 13x-36y+592 = 38,

From (2),

from (3), 13-117y+ 3512 = 234;

.. 2922-81y 196......... (4).

=

(126x-84y+210)—(120x-150y+210z)=60+(1053-3152+210),

whence 6x-39y+1052 = 60;

or 2x-13y+ 35% = 20,

and from (3), 2x-18y + 54% = 36;

13.

.. 79y=948, or y = 12;

16+5y 19

= 4, and x = 18+ 9y − 272 = 18.

xy=3(x+y), xz=8(x+2), 7yz = 9 (y + z), find x, y, z.