Question

Tìm x biết:
a) \(\dfrac{1}{4}-2x=2,5\)

b)\(\dfrac{x+3}{4}=\dfrac{3x-5}{5}\)​

Answer 1

Tìm x biết:

a) \(\dfrac{1}{4}\)- 2x = 2,5

⇒ 2x = \(\dfrac{1}{4}\)- 2,5

2x = -\(\dfrac{9}{4}\)

x = -\(\dfrac{9}{4}\): 2

x = -\(\dfrac{9}{8}\)

Answer 2

Tìm x biết:
a) $\frac{1}{4}-2x=2,5$

=> 2x = \(\dfrac{1}{4}-2,5\)

=> \(2x=-2,25\)

=> \(x=-1,125\)

b)$\frac{x+3}{4}=\frac{3x-5}{5}$​

=>\(5\left(x+3\right)=4\left(3x-5\right)\)

=> 5x + 15 = 12x - 20

=> 5x - 12x = -20-15

=> -17x = -35

=> x = \(\dfrac{35}{17}\)