CBSE Important Questions

1. Draw the graph :- (5 x 2 = 10)

1. 5x + 4y + 20 =0 (find the coordinate of the point on the graph when
   1. x = 8
   2. y = -5
2. Draw the graph of the equation 3 x + 4y = 14.Check whether (3, -2) is a point on the line.

2. Solve the following system of equation graphically

x + y = 7, 5x + 2y = 20 (4 marks)

3. Obtain graph (vertices of the triangle)

2y - x = 8
5y - x =14
y - 2x =1 (2 marks)

4.Solve the following by elimination method (substitution)

1. 2x – y = 5
   3x + 2y = 11 (2 marks)
2. (a + b) x + (a - b) y = a² + b²
   (a - b) x + (a + b) y = a² + b²

5. Solve by equating co-efficient (3 x 2 = 6)

1. 2 / x - 1 +3 /y + 1 = 2, 3/ x - 1 + 2/y + 1 = 13/6
2. 4x + 6/y = 15, 6x – 8/y = 14
3. 0.5 x +0.8 y = 3.4, 0.6x – 0.3y = 0.3

6. Solve equation by cross multiplication method. (3 x 2 = 6)

1. x/a + y/b = a + b, x/a² + y/b² = 2
2. ax + by = 1, bx + ay = (a + b)²/a² + b²
3. a/x – b/y = 0, ab²/x + a²b/y =a² +b²

7.Solve the value of k for which the following system of equation has No solution

1. x + 2y =3 , (k - 1)x + (k + 1)y =k + 2 (5 marks)
2. Find the value of k for which the system of equations
   4x + 5y = 0 , kx + 10y = 10 has Non zero solution

8. Find the whole no which when decreased by 20 is equal to 69 times the reciprocal of number . (3 marks)

9. 5 years hence the age of a man will be 3 times that of his son . 5 year ago the father’s age was seven times that of his son . what are their present age? (3 marks)

10. The sum of the numerator and denominator of a fraction is 4 more than twice the numerator . if the numerator and denominator are increased by 3, they are in the ratio 2 : 3. Determine the fraction . (3 marks)

11. A plane left 30 min later than its scheduled time and in order to reach the destination 1500 km away in time , it has to increase the speed by 250 km / hr from the usual speed . Find its usual speed . (3 marks)

12 . The area of a rectangle gets reduced by 8 square meters. If its length is reduced by 5 meters and width is increased by 3 meters. If we increased the length by 3 meters and breadth by 2 meters , the area is increased by 74 sq. meters. Find the length and breadth of the rectangle. (3 marks)