X•30+90=1200 X•(30+90)=1200 (750-25)•y=0 750-25•y=0 86+ икс + 138 = 250 452+y-230 = 222 (5 × 19) умножить на икс равно 3 800 × 20 (18 × 9) разделить на икс = 324 ÷ 4 5 × 5 - 2 × 2…

Let's solve each equation step by step.

1. Equation: \( X \cdot 30 + 90 = 1200 \)

   \[ X \cdot 30 = 1200 - 90 \] \[ X \cdot 30 = 1110 \] \[ X = \frac{1110}{30} = 37 \]

2. Equation: \( X \cdot (30 + 90) = 1200 \)

   \[ X \cdot 120 = 1200 \] \[ X = \frac{1200}{120} = 10 \]

3. Equation: \( (750 - 25) \cdot y = 0 \)

   \[ 725 \cdot y = 0 \] The only solution is \( y = 0 \).

4. Equation: \( 750 - 25 \cdot y = 0 \)

   \[ 750 = 25 \cdot y \] \[ y = \frac{750}{25} = 30 \]

5. Equation: \( 86 + x + 138 = 250 \)

   \[ x + 224 = 250 \] \[ x = 250 - 224 = 26 \]

6. Equation: \( 452 + y - 230 = 222 \)

   \[ 452 - 230 + y = 222 \] \[ 222 + y = 222 \implies y = 0 \]

7. Equation: \( (5 \times 19) \cdot x = 3800 \times 20 \)

   \[ 95x = 76000 \] \[ x = \frac{76000}{95} = 800 \]

8. Equation: \( \frac{18 \times 9}{x} = \frac{324}{4} \)

   \[ \frac{162}{x} = 81 \] \[ 162 = 81x \implies x = \frac{162}{81} = 2 \]

9. Equation: \( 5 \times 5 - 2 \times 2 \times 2 + x = 7 \times 7 \)

   \[ 25 - 16 + x = 49 \] \[ x = 49 - 9 = 40 \]

10. Equation: \( 4 \times 4 \cdot 2 \times 2 \times 2 \times 2 \times 2 - x = 3 \times 3 \)

    \[ 64 - x = 9 \] \[ x = 64 - 9 = 55 \]

11. Equation: \( 168 \cdot x \cdot 5 = 2520 \)

    \[ 840x = 2520 \] \[ x = \frac{2520}{840} = 3 \]

12. Equation: \( 221 \cdot 3 \cdot 15 = 13260 \)

    This equation is already satisfied.

13. Equation: \( \frac{93}{3} \div x = 31 \)

    \[ 31 \div x = 31 \implies x = 1 \]

14. Equation: \( \frac{128}{4} \div y = 16 \)

    \[ 32 \div y = 16 \implies y = 2 \]

15. Equation: \( 250(175 - y) = 125 \)

    \[ 175 - y = \frac{125}{250} = 0.5 \] \[ y = 175 - 0.5 = 174.5 \]

16. Equation: \( 629 - (333 - y) = 459 \)

    \[ 629 - 333 + y = 459 \] \[ y = 459 - 296 = 163 \]

17. Equation: \( (y + 100) - 60 = 240 \)

    \[ y + 40 = 240 \] \[ y = 200 \]

Summary of Solutions:

1. \( X = 37 \)
2. \( X = 10 \)
3. \( y = 0 \)
4. \( y = 30 \)
5. \( x = 26 \)
6. \( y = 0 \)
7. \( x = 800 \)
8. \( x = 2 \)
9. \( x = 40 \)
10. \( x = 55 \)
11. \( x = 3 \)
12. Equation is true (not a variable)
13. \( x = 1 \)
14. \( y = 2 \)
15. \( y = 174.5 \)
16. \( y = 163 \)
17. \( y = 200 \)