Toán 25-(x+5)=-415-(15-415) 34+(21-x)=(3747-30)-3746 16/07/2021 By Adalyn 25-(x+5)=-415-(15-415) 34+(21-x)=(3747-30)-3746
Đáp án: 1) x = 35 2) x = 84 Giải thích các bước giải: 1) 25 – (x+5)= -415 – (15 – 415) => 25 – (x+5)= -415 – 15 + 415 => 25 – (x+5)= [(-415) + 415] -15 => 25 – (x+5)= 0 – 15 => 25 – (x+5)= -15 => (x+5)= 25 – (-15) => x+5 = 40 => x = 40 – 5 => x = 35 2) 34 + (21 – x) = (3747 – 30) – 3746 => 34 + (21 – x) = 3 717 – 3746 => 34 + (21 – x) = – 29 => (21 – x) = (-29) – 34 => 21 – x = – 63 => x = 21 – (-63) => x = 84 Trả lời
a) 25-(x+5)=-415-(15-415) ⇔ 25 – x – 5 = -415 – 15 + 415 ⇔ 20 – x = -15 ⇔ x = 35. b) 34+(21-x) = (3747-30)-3746 ⇔ 34+21-x = 3747-30-3746 ⇔ 55-x = 1-30 ⇔ 55-x = -29 ⇔ x = 84. Trả lời