Secondary School (English Medium) (5 to 8) कक्षा ८ - CBSE Question Bank Solutions

If m – n = 16 and m² + n² = 400, then find mn.

Verify the following:

(a – b)(a – b)(a – b) = a³ – 3a²b + 3ab² – b³ 

Subtract b(b² + b – 7) + 5 from 3b² – 8 and find the value of expression obtained for b = – 3.

If `x - 1/x = 7` then find the value of `x^2 + 1/x^2`.

If the diagonals of a quadrilateral bisect each other, it is a ______.

If diagonals of a quadrilateral bisect each other, it must be a parallelogram.

The point of intersection of diagonals of a quadrilateral divides one diagonal in the ratio 1:2. Can it be a parallelogram? Why or why not?

Two sticks each of length 5 cm are crossing each other such that they bisect each other. What shape is formed by joining their endpoints? Give reason.

Two sticks each of length 7 cm are crossing each other such that they bisect each other at right angles. What shape is formed by joining their end points? Give reason.

a² – b² = (a + b) ______.

67² – 37² = (67 – 37) × ______ = ______.

(a + b)(a – b) = a² – b² 

The value of p for 51² – 49² = 100p is 2.

The value of (a + 1)(a – 1)(a² + 1) is a⁴ – 1.

Multiply the following: 

(a² – b²), (a² + b²) 

Using suitable identities, evaluate the following.

9.8 × 10.2

Using suitable identities, evaluate the following.

(35.4)² – (14.6)²

Using suitable identities, evaluate the following.

(69.3)² – (30.7)²

Using suitable identities, evaluate the following.

(9.7)² – (0.3)²