Question

cho(x-3)(3x+7)-3x^2=0 .Tìm x

Answer 1

x=-10,5

Answer 2

Ta có: (x - 3)(3x + 7) - 3x² = 0

=> 3x² - 2x - 21 - 3x² = 0

=> -2x - 21 = 0

=> -2x = 21

=> x = -10,5

Answer 3

\(\left(x-3\right)\left(3x+7\right)-3x^2=0\)

\(\Rightarrow x\left(3x+7\right)-3\left(3x+7\right)-3x^2=0\)

\(\Rightarrow3x^2+7x-9x-21-3x^2=0\)

\(\Rightarrow\left(3x^2-3x^2\right)+\left(7x-9x\right)=21\)

\(\Rightarrow-2x=21\)

\(\Rightarrow x=21:\left(-2\right)\)

\(\Rightarrow x=-10,5\)

Vậy x = -10,5

Answer 4

Cách làm