Question

Draw a graph of the equation 2x - 3y = 15. From the graph find the value of:
(i) x, when y = 3
(ii) y, when x = 0

Answer 1

We have
2x - 3y = 15
⇒ -3y = 15 - 2x
⇒ 3y = 2x - 15

⇒ y = `(2x - 15)/(3)`
When x = -2

⇒ y = `-(19)/(3)`
= -6.34
When x = 0

⇒ y = `-(15)/(3)` = -5
When x = 2

⇒ y = `-(11)/(3)` = -3.66

x	-2	-1	0	1	2
y	-6.34	-5.66	-5	-4.34	-3.66

Thus ordered pairs of 2x - 3y = 15 are {(-2, -6.34), (-1, -5.66), (0, -5),(1, - 4.34), (2, -3.66)}. Hence graph is a below.

(i) x, when y = 3
From graph we find that x = 12, when y = 3
(ii) y, when x = 0
Fro graph we find that y = -5, when x = 0.