Question

Tìm x

( 2,5 x + 5 ). ( -3 + 15x ) = 0

Answer 1

\(\left(2,5x+5\right).\left(-3+15x\right)=0\)

\(\Rightarrow2,5x+5=0\) hoặc \(-3+15x=0\)

*Với \(2,5x+5=0\Rightarrow2,5x=0-5=-5\)

..................................\(\Rightarrow x=-5:2,5=-2\)

*Với \(-3+15x=0\Rightarrow15x=0+3=3\)

...................................\(\Rightarrow x=3:15=\dfrac{3}{15}=\dfrac{1}{5}\)

Answer 2

(2,5x+5).(-3+15x)=0

Để A.B=0 thì A=0 hoặc B=0

TH1: 2,5x+5=0

:-)x=2

TH2: -3+15x=0

:-)15x=3:-)x=0,2

vậy x€{0,2 , 2 }