Question

3x²+5x=12

tìm x

Answer 1

\(\Leftrightarrow3x^2+5x-12=0\)

=>(x+3)(3x-4)=0

=>x=-3 hoặc x=4/3

Answer 2

3x²+5x=12
3x²+5x-12=0
3x²-4x+9x-12=0
x(3x-4)+3(3x-4)=0
(x+3)(3x-4)=0
\(\Rightarrow\)x+3=0 hoặc 3x-4=0
\(\Rightarrow\)x=-3 hoặc x=\(\dfrac{4}{3}\)