Q) Solve the following system of equations graphically:
2x + y = 6
2 x – y – 2 = 0
Find the area of the triangle so formed by two lines and x axis
Q31 B – Sample Question Paper – Set 1 – Maths Standard – CBSE 2026
Ans:
Part 1: Solving the linear equations:
Step 1: To plot the equations, let’s first find out the coordinates of points lying on these lines:
For line: 2 x + y = 6, we calculate coordinates of various points:
at X = 0, 2 (0) + y = 6 ∴ y = 6
at X = 1, 2 (1) + y = 6 ∴ y = 4
at X = 2, 2 (2) + y = 6 ∴ y = 2
at X = 3, 2 (3) + y = 6 ∴ y = 0
Hence, we get the following table:
Step 2: Similarly, for line: 2 x – y – 2 = 0, we calculate coordinates of various points:
For line: 2 x – y – 2 = 0, we calculate coordinates of various points:
at X = 0, 2 (0) – y – 2 = 0 ∴ y = – 2
at X = 1, 2 (1) – y – 2 = 0 ∴ y = 0
at X = 2, 2 (2) – y – 2 = 0 ∴ y = 2
at X = 3, 2 (3) – y – 2 = 0 ∴ y = 4
Hence, we get the following table:
Step 3: Now let’s plot both of these lines connecting each of the points:
From the diagram, we can see that the lines intersect each other at point (2, 2)
Therefore, the solution of the lines is (2, 2).
Part 2: Area of the triangle formed by two lines and X axis:
Step 4: Line 2 x + y = 6 cuts X – axis at (3, 0)
Line 2 x – y – 2 = 0 cuts X- axis at (1, 0)
Both lines cuts each other at (2, 2)
Hence, the 3 points of the triangle are: A (3,0), B (1, 0) and C (2,2)
AB = √ [(3 – 1)2 + (0 – 0)2 ] = √4 = 2 units
AC = √ [(3 – 2)2 + (0 – 2)2 ] = √5 units
BC = √ [(1 – 2)2 + (0 – 2)2 ] = √5 units
From the triangle, Height = √ (√5)2 – 12) = √(5 – 1) = √4 = 2 units
∴ Area of the triangle = 1/2 x Base x Height
= 1/2 x 2 x 2 = 2 sq units
Therefore, the area of the triangle between lines & X-axis is 2 sq. units.
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