Question

5-x=900:15
c:(700-685)=135
а+420 = 205-8
10. y-800=9800

Answer 1

1) $5 - x = 900$ ÷ $15$

$5 - x = 60$

$x = 5 - 60$

$x = -55$

_____

$5 - -55 = 900$ ÷ $15$

$5 - -55 = 60$

$5 + 55 = 60$

$60 = 60$

Ответ: $x = -55$

2) $c$ ÷ $(700 - 685) = 135$

$c$ ÷ $15 = 135$

$c = 135$ × $15$

$c = 2025$

_______

$2025$ ÷ $(700 - 685) = 135$

$2025$ ÷ $15 = 135$

$135 = 135$

Ответ: $c = 2025$

3) $a + 420 = 205 - 8$

$a + 420 = 197$

$a = 197 - 420$

$a = -223$

______

$-223 + 420 = 205 - 8$

$-223 + 420 = 197$

$197 = 197$

Ответ: $a = -223$

4) $10y - 800 = 9800$

$10y = 9800 + 800$

$10y = 10600$

$y = 10600$ ÷ $10$

$y = 1060$

______

$10$ × $1060 - 800 = 9800$

$10600 - 800 = 9800$

$9800 = 9800$

Ответ: $y = 1060$