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!

a: Ta có: \(A=\left(2x+3\right)\left(4x^2-6x+9\right)-2\left(4x^3-1\right)\)

\(=8x^3+27-8x^3+2\)

=29

b: Ta có: \(B=\left(64x^3-1\right)-\left(4x-3\right)\left(16x^2+3\right)\)

\(=64x^3-1-64x^3-12x-48x^2+9\)

\(=-12x+8\)

c: Ta có: \(2\left(x^3+y^3\right)-3\left(x^2+y^2\right)\)

\(=2\left(x^2+xy+y^2\right)-3\left(-2xy\right)\)

\(=2x^2+2xy+2y^2+6xy\)

\(=2x^2+8xy+2y^2\)

giúp mik đi ạ đang gấp

x+1<x+2<x+3<x+4 ( với mọi x)

\(\dfrac{1}{100}\) < \(\dfrac{1}{99}\)<\(\dfrac{1}{3}\) <\(\dfrac{1}{2}\)

=>\(\dfrac{x+1}{100}\)+\(\dfrac{x+2}{99}\) <\(\dfrac{x+3}{3}\)+\(\dfrac{x+4}{2}\) là đúng

Ta có : x² - 2x - (x + 3)² = 6

<=> x² - 2x - x² - 6x - 9 = 6

<=> -8x - 9 = 6 

=> -8x = 15

=> x = \(\frac{15}{-8}\)

a, \(\dfrac{x}{3}=\dfrac{8}{12};12:3=4\)\(;8:4=2\)

⇒\(x=\dfrac{2}{3}\)

a: \(\dfrac{x}{3}=\dfrac{8}{12}\)

nên x/3=2/3

hay x=2

b: \(x+\dfrac{1}{15}=\dfrac{1}{3}\)

\(\Leftrightarrow x=\dfrac{1}{3}-\dfrac{1}{15}=\dfrac{5}{15}-\dfrac{1}{15}=\dfrac{4}{15}\)

c: \(x\cdot\dfrac{4}{7}-\dfrac{2}{7}=\dfrac{5}{7}\)

\(\Leftrightarrow x\cdot\dfrac{4}{7}=\dfrac{5}{7}+\dfrac{2}{7}=1\)

hay x=7/4

d: \(\Leftrightarrow x\cdot\dfrac{3}{4}-\dfrac{5}{4}=-\dfrac{1}{2}\)

\(\Leftrightarrow x\cdot\dfrac{3}{4}=-\dfrac{2}{4}+\dfrac{5}{4}=\dfrac{3}{4}\)

hay x=1

=-77.16

=-1232

a: \(M=\left(\dfrac{-3}{7}x^3y\right)\cdot\dfrac{7xy^3}{12}-x^2y^2\cdot\left(-\dfrac{3}{4}x^2y^2\right)\)

\(=\dfrac{-1}{4}x^4y^4+\dfrac{3}{4}x^4y^4\)

\(=\dfrac{1}{2}x^4y^4\)

b: Hệ số là 1/2

Biến là \(x^4;y^4\)

bậc là 4+4=8

c: Thay x=-1 và y=-2 vào M, ta được:

\(M=\dfrac{1}{2}\left(-1\right)^4\cdot\left(-2\right)^4=\dfrac{1}{2}\cdot16=8\)

\(2^{x+1}-2^x=3^2\)

\(\Rightarrow2^x\cdot\left(2-1\right)=9\)

\(\Rightarrow2^x=9\)

\(\Rightarrow x\in\varnothing\)

\(2^{x+1}-2^x=3^2\)

=>2^x*2-2^x=9

=>2^x=9

=>\(x\in\varnothing\)

23/12

1/3

a.x=23/12

b.x=1/3

x = 5/3+1/4

x = 23/12

x = 1/2 x 2/3

x= 1/3