Tìm số nguyên x: a) 46 – x = –21 + (–87) b) x – 96 = (443 – x) – 15 c) (–x + 281 +534) = 499 + (x – 48) d) –(754 + x) = (x – 12 – 741) – 23.

Lời giải

a) 46 – x = –21 + (–87)

⇔ 46 – x = –108

⇔ x = 46 – (–108)

⇔ x = 154

Vậy x = 154.

b) x – 96 = (443 – x) – 15

⇔ x – 96 = 443 – x – 15

⇔ x – 96 = 428 – x

⇔ x + x = 428 + 96

⇔ 2x = 524

⇔ x = 262

Vậy x = 262.

c) (–x + 281 +534) = 499 + (x – 48)

⇔ –x + 281 +534 = 499 + x – 48

⇔ –x + 815 = 451 + x

⇔ 815 – 451 = x + x

⇔ 364 = 2x

⇔ 182 = x

Vậy x = 182.

d) –(754 + x) = (x – 12 – 741) – 23

⇔ –754 – x = x – 12 – 741 – 23

⇔ –754 – x = x – 776

⇔ –754 + 776 = x + x

⇔ 22 = 2x

⇔ 11 = x

Vậy x = 11.