Assertion (A) : If the volume of a cube is a³ + b³ + 3ab(a + b), then the edge of the cube is (a + b)

Reason (R) : (1^st term + 2^nd term)³ = (1^st term)³ + 3(1^st term)² .(2^nd term) + 3(2^nd term)² .(1^st term) + (2^nd term)³.

1. Both A and R are correct, and R is the correct explanation for A.

2. Both A and R are correct, and R is not the correct explanation for A.

3. A is true, but R is false.

4. A is false, but R is true.

Assertion (A) : 687 x 687 - 313 x 313 = 37400

Reason (R) : The product of the sum and difference of the same two terms = The square of their difference.

1. Both A and R are correct, and R is the correct explanation for A.

2. Both A and R are correct, and R is not the correct explanation for A.

3. A is true, but R is false.

4. A is false, but R is true.

Evaluate :

(2a + 0.5)(7a - 0.3)

Evaluate :

(9 - y) (7 + y)