Question

Tìm x thuộc Z biết:

a) 2.(4x-2x)-7x=16

b) -2[x+(-7)]+(x+3)=12

c) 10.(x-7)=8(x-4)+x

Answer 1

\(a,2\cdot\left(4x-2x\right)-7x=16\\ 2\cdot2x-7x=16\\ 4x-7x=16\\ -3x=16\\ x=-16:3\\ x=\dfrac{-16}{3}\\ b,-2\left[x+\left(-7\right)\right]+\left(x+3\right)=12\\ -2\cdot x+\left(-2\right)\cdot\left(-7\right)+x+3=12\\ -2x+x+14+3=12\\ -x+17=12\\ -x=-5\\ \Rightarrow x=5\\ c,10\cdot\left(x-7\right)=8\left(x-4\right)+x\\ 10x-10\cdot7=8x-8\cdot4+x\\ 10x-70=9x-32\\ 10x-70+32=9x\\ 10x-38=9x\\ \Rightarrow x=38\)