The coefficient of correlation between two variables X

Simplify the following expression:

    (525 +175) ² - (525 – 175) ² / (525 × 175)

What will come in the place of question mark (?) in the given expression?

(11/45) of 225 + 3 X 75 = ? X (72 ÷ 6 + 4)

(165 × 12) ÷ 45 + 110 = ? × 2

30% of 750 + ?% of 400 = 25% of 1016 + 3

46% of 13/92 × 24/91 × 3500 =?

Simplify the following expression and find the final value:

(18 ÷ 6 of 2 + 7 of 5) ÷ 5

15% of 5000 - √900 = ? + 10% of 1800

7, 8, 12, 21, 37, ?

((9.77)⁰- 〖(0.1)〗^(-1))/(〖(6/2⁴ )〗^(-1) ×(3/2)³+ 〖((-2)/6)〗^(-1) ) = ?

654.056 + 28.9015 × 44.851 – 43.129 =?