Find the quotient and the remainder when $2 x^{2}-7 x-15$ is divided by

$2 x+1$

Factorise

$x^{2}+9 y^{2}+4+6 x y+12 y+4 x$

Give possible expressions for the length and breadth of a rectangle whose area is given as $\left(20 x^{2}+22 x+6\right)$ square units. $(x>0)$

Classify the following as linear, quadratic or cubic polynomial

$8 x^{3}-343$

Evaluate the following products without multiplying directly

$76 \times 82$