Question

tìm x biết:

a, \(-4x\left(x-5\right)-2x\left(8-2x\right)=-3\)

b, \(\left|2x-1\right|=5\)

Answer 1

a) -4x(x-5)-2x(8-2x)=-3

<=> -2x(2x-10+8-2x)=-3

<=> -2x.(-2)=-3

<=> 4x=-3

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

b)|2x-1|=5

TH1: 2x-1=5

=> 2x=5+1

=> 2x=6

=> x=3

TH2: 2x-1=-5

=> 2x=-5+1

=> 2x=-4

=> x= -2

Answer 2

a,

b,

Answer 3

a, -4x (x - 5) - 2x (8 - 2x) \(=\) -3

⇒ -4x\(^2\) + 20x + 4x\(^2\) -16x \(=\) -3

⇒ 4x \(=\) -3

⇒ x \(=\) \(\dfrac{-3}{4}\)

b, |2x - 1| \(=\) 5

⇒ 2x - 1 \(=\) 5 hoặc 2x - 1 \(=\) -5

⇒x \(=\) 3 hoặc x \(=\) -1

\(=\)\(=\)