List of top Questions asked in CBSE Class IX

1. an object with a constant acceleration but with zero velocity 
2. an object moving with an acceleration but with uniform speed. 
3. an object moving in a certain direction with an acceleration in the perpendicular direction.

Use suitable identities to find the following products: 

(i) (x + 4) (x + 10) 

(ii) (x + 8) (x – 10) 

(iii) (3x + 4) (3x – 5) 

(iv) \((y^ 2 + \frac{3 }{ 2}) (y^ 2 – \frac{3 }{ 2}) \)

(v) (3 – 2x) (3 + 2x)

Evaluate the following products without multiplying directly: 

(i) 103 × 107 (ii) 95 × 96 (iii) 104 × 96

1. Keep cup A empty 
2. Put one teaspoon sugar in cup B 
3. Put one teaspoon salt in cup C 
4. Put one teaspoon sugar in the boiled potato cup D. Keep these for two hours. Then observe the four potato cups and answer the following: 

1. Explain why water gathers in the hollowed portion of B and C. 
2.  Why is potato A necessary for this experiment? 
3. Explain why water does not gather in the hollowed-out portions of A and D.

Factorise the following using appropriate identities: 

(i) 9x ² + 6xy + y 2 

(ii) 4y ² – 4y + 1 

(iii) x ² – \(\frac{y^2 }{ 100}\)

Expand each of the following, using suitable identities: 

(i) (x + 2y + 4z) 2 (ii) (2x – y + z) ² (iii) (–2x + 3y + 2z) ² 

(iv) (3a – 7b – c) ² (v) (–2x + 5y – 3z) ² (vi) [ \(\frac{1 }{ 4}\) a - \(\frac{1 }{ 2}\) b + 1]²

Write the coefficients of x 2 in each of the following: 

(i) 2 + x ² + x 

(ii) 2 – x ² + x 3 

(iii) \(\frac{π }{ 2}\) x² + x 

(iv) √2 x -1

Find the value of the polynomial 5x – 4x ² + 3 at 

(i) x = 0 (ii) x = –1 (iii) x = 2