Question

Solve the following simultaneous equations graphically:

x + y = 6, x – y = 4

Answer 1

x + y = 6

∴ y = 6 – x

x	–1	0	2	4
y	7	6	4	2
(x, y)	(–1, 7)	(0, 6)	(2, 4)	(4, 2)

x – y = 4

∴ y = x – 4

x	0	1	2	3
y	– 4	– 3	– 2	– 1
(x, y)	(0, – 4)	(1, – 3)	(2, – 2)	(3, – 1)

The coordinates of the point of intersection are (5, 1).

The solution of the given simultaneous equations is x = 5, y = 1.