Question

[Lê Minh Chiến]

a)4X-(X+1/2)=2X-(1/2-5)

b)2/3-1/3(X/-3/2)-1/2 nhân (2X+1)=5

(X/-3/2 là hỗn số)  Giúp mình với

Answer 1

[Huỳnh Quang Sang]

a) \(4x-\left(x+\frac{1}{2}\right)=2x-\left(\frac{1}{2}-5\right)\)

=> \(4x-x-\frac{1}{2}=2x-\left(-\frac{9}{2}\right)\)

=> \(3x-\frac{1}{2}=2x+\frac{9}{2}\)

=> \(3x-\frac{1}{2}-2x-\frac{9}{2}=0\)

=> \(\left(3x-2x\right)+\left(-\frac{1}{2}-\frac{9}{2}\right)=0\)

=> x - 5 = 0 => x = 5

b) \(\frac{2}{3}-\frac{1}{3}\left(\frac{x}{-\frac{3}{2}}\right)-\frac{1}{2}\left(2x+1\right)=5\)

=> \(\frac{2}{3}-\frac{1}{3}\left[x\cdot\left(-\frac{2}{3}\right)\right]-x-\frac{1}{2}=5\)

=> \(\frac{2}{3}-\frac{1}{3}\left(-\frac{2x}{3}\right)-x-\frac{1}{2}=5\)

=> \(\frac{2}{3}-\left(-\frac{2x}{9}\right)-x-\frac{1}{2}=5\)

=> \(\frac{2}{3}+\frac{2x}{9}-x-\frac{1}{2}=5\)

=> \(\frac{6}{9}+\frac{2x}{9}-x=\frac{11}{2}\)

=> \(\frac{6+2x}{9}-x=\frac{11}{2}\)

=> \(\frac{6+2x}{9}-\frac{9x}{9}=\frac{11}{2}\)

=> \(\frac{6-7x}{9}=\frac{11}{2}\)

=> \(6-7x=\frac{11}{2}\cdot9=\frac{99}{2}\)

=> \(7x=6-\frac{99}{2}\)

=> \(7x=-\frac{87}{2}\)

=> \(x=\left(-\frac{87}{2}\right):7=\left(-\frac{87}{2}\right)\cdot\frac{1}{7}=-\frac{87}{14}\)

p/s : nếu gõ kiểu latex \(\frac{x}{-\frac{3}{2}}\)thì cái đây không phải là hỗn số đâu.Bạn nên kiểm tra đề :)))