Question

Solve the following simultaneous equations graphically.

x + y = 6 ; x – y = 4

Answer 1

The given simultaneous equations are
x + y = 6
∴ y = 6 – x

y = 6 – x ∴ y = 6 – 0 ∴ y = 6

y = 6 – x ∴ y = 6 – 2 ∴ y = 4

y = 6 – x ∴ y = 6 – 6 ∴ y = 0

 

x	0	2	6
y	6	4	0
(x, y)	(0, 6)	(2, 4)	(6, 0)

x – y = 4
∴ y = x – 4

y = x – 4 ∴ y = 0 – 4 ∴ y = –4

y = x – 4 ∴ y = 4 – 4 ∴ y = 0

y = x – 4 ∴ y = 5 – 4 ∴ y = 1

 

x	0	4	5
y	–4	0	1
(x, y)	(0, –4)	(4, 0)	(5, 1)

 Point of intersection of the two lines is (5, 1).

∴ x = 5 and y = 1 is the solution of the simultaneous equations x + y = 6 and x – y = 4.