Question

The graph of the equations 2x − y − 4 = 0 and x + y + 1 = 0 intersect each other in point P(a, b), then find the coordinates of P?

Answer 1

The given equations are

2x − y − 4 = 0

∴ y = 2x – 4

x	0	2	3	4
y	− 4	0	2	4
(x, y)	(0, − 4)	(2, 0)	(3, 2)	(4, 4)

x + y + 1 = 0

∴ y = – x – 1

x	0	1	2	−1
y	−1	−2	−3	0
(x, y)	(0, −1)	(1, −2)	(2, −3)	(−1, 0)

The two lines intersect at P(1, – 2).

∴ The coordinates of P are (1, – 2).