## Giúp mình với vote 5 sao 1.Tìm x biết a. 4.(18-5x)-12(3x-7)=15(2x-16)-6(x+14) b. 2(5x-8)-3(4x-5)=4(3x-4)+11

Question

Giúp mình với vote 5 sao
1.Tìm x biết
a. 4.(18-5x)-12(3x-7)=15(2x-16)-6(x+14)
b. 2(5x-8)-3(4x-5)=4(3x-4)+11

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2 năm 2021-08-22T15:00:29+00:00 2 Answers 25 views 0

## Answers ( )

1. Đáp án: $a$) $x=6$

$b$) x = 2/7

Giải thích các bước giải:

$1$.

$a$, 4.(18-5x)-12(3x-7)=15(2x-16)-6(x+14)

⇔ 72 – 20x – 36x + 84 = 30x – 240 – 6x – 84

⇔ 72 + 84 + 84 + 240 = 30x-6x + 36x + 20x

⇔ 480 = 80x

⇔ x = 6

Vậy $x=6$

$b$, 2(5x-8)-3(4x-5)=4(3x-4)+11

⇔ 10x – 16 – 12x + 15 = 12x – 16 + 11

⇔ 10x – 12x – 12x = -16 + 11 – 15 + 16

⇔ -14x = -4

⇔ x = 2/7

Vậy x=2/7

2. Bài lm nek

Nhớ vote cho mk 5 sao nhá ????

Câu a.

4 (18 – 5x) – 12 (3x – 7) = 15 (2x – 16) – 6 (x + 14)

-> (72 – 20x) – (36x – 84) = (30x – 240) – (6x + 84)

-> 72 – 20x – 36x + 84 = 30x – 240 – 6x – 84

-> (72 + 84) + (-20x – 36x) = (30x – 6x) + (-240 – 84)

-> 156 – 56x = 24x – 324

-> 156 + 324 = 24x + 56x

-> 80x = 480

-> x = 480/80

-> x = 6

Câu b.

2 (5x – 8) – 3 (4x – 5) = 4 (3x – 4) + 11

-> (10x – 16) – (12x – 15) = (12x – 16) + 11

-> 10x – 16 – 12x + 15 = 12x – 16 + 11

-> (15 – 16) + (10x – 12x) = 12x – 5

-> -1 – 2x = 12x – 5

-> -1 + 5 = 12x + 2x

-> 14x = 4

-> x = 4/14

-> x = 2/7