Giải phương trình 1/(x+4)(x+5)+1/(x+5)(x+6)+1/(x+6)(x+7)=1/18
Giải thích
1x+4x+5+1x+5x+6+1x+6x+7=118x≠−4;−5;−6;−7⇔1x+4−1x+5+1x+5−1x+6+1x+6−1x+7=118⇔1x+4−1x+7=118⇔x+7−x−4x+4x+7=118⇔x2+11x−26=0⇔x=2x=−13(tm)
1x+4x+5+1x+5x+6+1x+6x+7=118x≠−4;−5;−6;−7⇔1x+4−1x+5+1x+5−1x+6+1x+6−1x+7=118⇔1x+4−1x+7=118⇔x+7−x−4x+4x+7=118⇔x2+11x−26=0⇔x=2x=−13(tm)