If (x +y) = 6 and x² + y² = 20 then find the value of (x - y) ².

12 × 15 + 27 – ? = 28% of 400

If 2x + 3y - 5z = 18 , 3x + 2y + z = 29 and x + y + 3z = 17 , then what is the value of xy + yz + zx ? 

How many perfect squares lie between 120 and 300? 

[(169×121)÷(11×13)]-3=?

Simplify the following equation.
$${(785.785.785+435.435.435) \over(785)^{2}+(435)^{2}-(785)(435)}$$

Direction : What should come in place of the question (?) in the following question.

(47 × 588) ÷ ( 28 × 120)=?

Solve the following equation 24 + 4 ÷ 4