3.2x—3=45

3.2x=45+3

3.2x=48

2x=48:3

2x=16

x=16:2

x=8

4x .3+12=120

4x.3=120–12

4x.3=108

4x=108:3

4x=36

x=36:4

x=9

\(3.2x-3=45\)

\(3.2x=45+3\)

\(3.2x=48\)

\(2x=\frac{48}{3}\)

\(2x=16\)

\(x=8\)

Vậy \(x=8\)

\(1500:\left[\left(36x+40\right):x\right]=30\)

\(\left(36x+40\right):x=1500:30\)

\(36x+40=50x\)

\(50x-36x=40\)

\(14x=40\)

\(x=\frac{40}{14}\)

\(x=\frac{20}{7}\)

Vậy \(x=\frac{20}{7}\)

a)3.2x-3 = 45

3.(2x-1) = 45

2x-1 = 45 : 3

2x-1 = 15

2x = 16

x = 8

các bài cn lại bn dựa vào phần a mak lm nha!

x - 28 = 4 x 3

x - 28 = 12

x        = 12 + 28

x        = 40

Nếu cần bạn có thể kết bạn với mk mình giảng cho

X - 28 = 4 x 3

X - 28 = 12

X        = 12 + 28

X        = 40

X - 28 : 3 = 4

X - 28 = 4 x 3

X - 28 = 12

X = 12 + 28

X = 40

Có thấy phân số nào đâu bn

= ( 21 + 12 - 3 + 44 + 55 ) x 0 

= 0 

( 21 + 12 - 3 + 44 + 55) x ( 2 x 6 -4x3) = (21+12-3+44+55)x( 12-12)

=(21+12-3+44+55)x0 = 0

đúng

câu 58: C
câu 59: A
câu 60: A

58.C

59.A

60.A

c - 211

a: Ta có: \(\left[\left(6x-39\right):3\right]\cdot28=5628\)

\(\Leftrightarrow\left(6x-39\right):3=201\)

\(\Leftrightarrow6x-39=603\)

\(\Leftrightarrow6x=642\)

hay x=107

b: Ta có: \(4x^3+12=120\)

\(\Leftrightarrow4x^3=108\)

\(\Leftrightarrow x^3=27\)

hay x=3

c: Ta có: \(1500:\left[\left(30x+40\right):x\right]=30\)

\(\Leftrightarrow\left(30x+40\right):x=50\)

\(\Leftrightarrow30x+40=50x\)

hay x=-2

\(a,223-6\left(x+5\right)=49\\ 6\left(x+5\right)=223-49\\ 6\left(x+5\right)=174\\ x+5=174:6\\ x+5=29\\ x=29-5\\ x=24\\ ----\\ b,4x^3+12=120\\ 4x^3=120-12\\ 4x^3=108\\ x^3=108:4\\ x^3=27\\ Mà:3^3=27\\ Nên:x^3=3^3\\ Vậy:x=3\)

a. 223 - 6. (x + 5) = 49

6. (x + 5) = 223 - 49

6. (x + 5) = 174

x + 5 = 174 : 6

x + 5 = 29

x = 29 - 5

x = 24

b. 4x³ + 12 = 120

4x³ = 120 - 12 = 108

x³ = 108 : 4 = 27

x³ = 3³

x= 3

Tại x = 3, ta có: A = 4x = 4.3 = 12

Đáp án cần chọn là: D

nhanh giùm mình được không

Bài 1: 

a) Ta có: \(P=1+\dfrac{3}{x^2+5x+6}:\left(\dfrac{8x^2}{4x^3-8x^2}-\dfrac{3x}{3x^2-12}-\dfrac{1}{x+2}\right)\)

\(=1+\dfrac{3}{\left(x+2\right)\left(x+3\right)}:\left(\dfrac{8x^2}{4x^2\left(x-2\right)}-\dfrac{3x}{3\left(x-2\right)\left(x+2\right)}-\dfrac{1}{x+2}\right)\)

\(=1+\dfrac{3}{\left(x+2\right)\left(x+3\right)}:\left(\dfrac{4}{x-2}-\dfrac{x}{\left(x-2\right)\left(x+2\right)}-\dfrac{1}{x+2}\right)\)

\(=1+\dfrac{3}{\left(x+2\right)\left(x+3\right)}:\dfrac{4\left(x+2\right)-x-\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}\)

\(=1+\dfrac{3}{\left(x+2\right)\left(x+3\right)}\cdot\dfrac{\left(x-2\right)\left(x+2\right)}{4x+8-x-x+2}\)

\(=1+3\cdot\dfrac{\left(x-2\right)}{\left(x+3\right)\left(2x+10\right)}\)

\(=1+\dfrac{3\left(x-2\right)}{\left(x+3\right)\left(2x+10\right)}\)

\(=\dfrac{\left(x+3\right)\left(2x+10\right)+3\left(x-2\right)}{\left(x+3\right)\left(2x+10\right)}\)

\(=\dfrac{2x^2+10x+6x+30+3x-6}{\left(x+3\right)\left(2x+10\right)}\)

\(=\dfrac{2x^2+19x-6}{\left(x+3\right)\left(2x+10\right)}\)