Question

2 x (x - 1) - 7 = 9

Chi tiết

Answer 1

\(2 . (x - 1) - 7 = 9\)

\(2 . (x - 1) =9+7\)

\(2.(x-1)=16\)

\(x-1=16:2\)

\(x-1=8\)

\(x=8+1\)

\(x=9\)

Answer 2

2x(x-1)=9+7=16
    x-1  =16:2=8
    x     = 8+1 =9

Answer 3

\(2.\left(x-1\right)-7=9\)

\(\Rightarrow2.\left(x-1\right)=9+7\)

\(\Rightarrow2.\left(x-1\right)=16\)

\(\Rightarrow x-1=8\)

\(\Rightarrow x=9\)

Answer 4

\(2\times\left(x-1\right)-7=9\)

\(\Leftrightarrow2x-2-7=9\)

\(\Leftrightarrow2x=18\)

\(\Leftrightarrow x=9\)

Answer 5

\(2\left(x-1\right)-7=9\)

\(2\left(x-1\right)=16\)

\(x-1=8\)

\(x=9\)

 

Answer 6

2.(x-1)-7=9

2(x-1)=16

=> x-1=8

=>x=9

Answer 7

=> \(2x^2-2x=9+7=16\)

=> \(2x^2-2x-16=0\)

\(\Delta=\left(-2\right)^2-4.2.-16=132>0\)

=> pt có 2 nghiệm pt

\(x_1=\dfrac{2+\sqrt{132}}{4};x_2=\dfrac{2-\sqrt{132}}{4}\)