Question

Check whether the following are solutions of the equation y = 2x - 4, (i) (0,-4) (ii) (1,2).​

Answer 1

Answer:

y=2x-4

(I)put x=0and y=-4

-4=2×0-4

-4=0-4

-4=-4

(ii) put x=1and y=2

2=2×1-4

2=2-4

2≠-2

Answer 2

Answer:

Given y−2x=4⇒y=2x+4

Table of Solutions

xy = 2x + 4(x, y)Point0y = 2(0) + 4 = 4(0, 4)A(0, 4)2y = 2(-2) + 4 = 0(-2, 0)B(-2, 0)1y = 2(1) + 4 = 6(1, 6)C(1, 6)Plotting the points A, B and C on the graph paper and joint them to get the straight line BC as shown in graph sheet. This line is the required graph of the equation y - 2x = 4.

(i) Plot the point (2, 8) on the graph paper. From the graph it is clear that the point (2, 8) lies on the line.

Checking algebraically: On substituting (2, 8) in the given equation, we get

LHS y−2x=8−2×2=8−4=4 RHS, So (2, 8) is a solution

(ii) Plot the point (4, 2) on the graph paper. You fin that (4, 2) does not lie on the line.

Checking algebraically: By substituting (4, 2) in the given equation we have

LHS =y−2x=2−2×4=2−8=−6=RHS, So (4, 2) is not a solution.