What is the extension of saved file in MS

If x + y + 3 = 0, then find the value of x³ + y³ – 9xy + 9.

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

(40% of 900 + 70% of 1800) ÷ 108 = ?

(15/8) x [6924 – 2124] + 910 = ? + 190

Simplify: (2³×3²) ÷6

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

25% of 240 + √? = (2/3) × 120

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

(17/27) of 162 + ?² = 632 - (73 - 12) X 5

46.2 × 8.4 × 3 + ? = 1200

56 x 8 – 65% of 40 = ? + 14 x √625