a.3-2x=3(x+1)-x-2 ⇔ 3 − 2 x = 3 x + 3 − x − 2 ⇔3−2x=3x+3−x−2 ⇔ − 2 x + x − 3 x = − 3 + 3 − 2 ⇔−2x+x−3x=−3+3−2 ⇔ − 4 x = − 2 ⇔−4x=−2 ⇔ x = 1 2 ⇔x=12 Vậy S={1/2}
b,, 2 x ( x − 3 ) + 5 ( x − 3 ) = 0 a,2x(x−3)+5(x−3)=0 ⇔ ( x − 3 ) ( 2 x + 5 ) = 0 ⇔(x−3)(2x+5)=0 ⇔ [ x − 3 = 0 2 x + 5 = 0 ⇔ ⎡ ⎣ x = 3 x = − 5 2 ⇔[x−3=02x+5=0⇔[x=3x=−52 Vậy nghiệm của pt là S = { 3 ; − 5 2 }