Question

Solve the following pair of simultaneous equations graphically.

3x + 2y + 4 = 0

x + 3y = 1

Answer 1

Given:

3x + 2y + 4 = 0

x + 3y = 1

Step 1: Rearranging equations in the form y = mx + c

3x + 2y + 4 = 0

2y = −3x −4

y = `(−3x − 4)/2`

x + 3y = 1

3y = 1 − x

y = `(1 − x)/3`

x = −2, y = 1

y = `(−3x − 4)/2`

x	Calculation y	y	(x, y)
−2	`(−3(−2) − 4)/2 = (6 − 4)/2`	1	(−2, 1)
0	`(−3(0) − 4)/2 = (− 4)/2`	−2	(0, −2)
2	`(−3(2) − 4)/2 = (−10)/2`	−5	(2, −5)

y = `(1 − x)/3`

x	Calculation	y	(x, y)
−2	`(1 + 2)/3 = 3/3`	1	(−2, 1)
0	`(1 − 0)/3`	`1/3`	`(0, 1/3)`
1	`1 − 1/3`	0	(1, 0)