Question

  ai giúp với mai thi rồi ! Help! 

Answer 1

1: 2x-12=3

=>2x=12+3=15

=>\(x=\dfrac{15}{2}\)

2: \(7x-\left(2x+3\right)=5\left(x-2\right)\)

=>\(7x-2x-3=5x-10\)

=>-3=-10(vô lý)

3: \(2x+5=20-3x\)

=>2x+3x=20-5

=>5x=15

=>x=3

4: \(4\left(x+1\right)-2=10\)

=>4(x+1)=12

=>x+1=3

=>x=2

5: 3x-6=0

=>3x=6

=>\(x=\dfrac{6}{3}=2\)

6: \(\dfrac{3}{4}x+12=0\)

=>\(\dfrac{3}{4}x=-12\)

=>\(x=-12:\dfrac{3}{4}=-16\)

7: \(-24+\dfrac{3}{8}x=0\)

=>\(\dfrac{3}{8}x=24\)

=>\(x=24:\dfrac{3}{8}=24\cdot\dfrac{8}{3}=64\)

8: 5x-30=10

=>5x=30+10=40

=>\(x=\dfrac{40}{5}=8\)

9: 5(3x-4)=2x+6

=>15x-20=2x+6

=>13x=26

=>x=2

10: 2x+6=0

=>2x=-6

=>\(x=-\dfrac{6}{2}=-3\)

11: 5x-3=2x+61

=>5x-2x=61+3

=>3x=64

=>\(x=\dfrac{64}{3}\)