Giải thích các bước giải:
a) ( 2x+5 )( x-3) /2 - x(x-3) = -1/2
⇔ (2x+5)(x−3)−2x(x−3)=−1
⇔ 2x²−6x+5x−15−2x²+6x=−1
⇔ 5x−15=−1
⇔ 5x=−1+15
⇔ 5x=14
⇔ x=$\frac{14}{5}$
b) x( x^2+x+1 ) - (x+1)(x-1)x = x^2-2
⇔ x(x²+x+1)−x(x+1)(x−1)=x²−2
⇔ x³+x²+x−x³+x²−x²+x=x²−2
⇔ x²+2x=x²−2
⇔ 2x=−2
⇔ x=−1
c) ( x+1)^2 - ( x-1)^2 = 6( x^2+x+1)
⇔ x²+2x+1−x²+2x−1=6x²+6x+6
⇔ 4x=6x²+6x+6
⇔ 4x−6x²−6x−6=0
⇔ −2x−6x²−6=0
⇔ ∅
d) ( x+2)( x+4) + ( x+3)(x-3) = ( 2x+3)(x+1)
⇔ x²+4x+2x+8+x²−3²=2x²+2x+3x+3
⇔ x²+4x+2x+8+x²−9=2x²+2x+3x+3
⇔ 2x²+6x−1=2x²+2x+3x+3
⇔ 2x²+6x−1=2x²+5x+3
⇔ 6x−1=5x+3
⇔ 6x=5x+3+1
⇔ 6x=5x+4
⇔ 6x−5x=4
⇔ x=4
xin hay nhất! :)))