y = (5x – 10)/2 ; 4x + 5 = - y

iii. y = ^{(5x – 10)}/₂ ; 4x + 5 = - y

Sol. y = ^{(5x – 10)}/₂

∴ 2y = 5x – 10

∴ – 5x + 2y = – 10

Changing the sign,

∴ 5x – 2y = 10

Now, 4x + 5 = – y

∴  4x + y = – 5

D	=	5	-2	=	(5 × 1) – (4 × -2)	=	5 + 8	=	13
		4	1

DX	=	10	-2	=	(10 × 1) – (-5 × -2)	=	10 – 10	=	0
		-5	1

DY	=	5	10	=	(5 × -5) – (4 × 10)	=	-25  - 40	=	-65
		4	-5

By Cramer's rule,

x	=	Dx	=	0	=	0
		D		13

y	=	Dx	=	-65	=	-5
		D		13

∴ x = 0 and y = – 5 is the solution of given simultaneous equations.